ventilation in historic buildings b-2

Ventilation in historic buildings

1 ( 60)Ventilation in historic buildings

CONTENTS

s. 2 Foreword

3 Ventilation history, domestic buildings

6 Ventilation history, non- domestic buildings

9 Swedish regulations regarding ventilation

12 Swedish legislative protection for historic buildings

14 Ventilation principles

16 Good advice

23 Eight examples in Sweden:

24 1. Amiralitetshuset, Skeppsholmen, Stockholm

29 2. Sjöreservens kasern, Skeppsholmen, Stockholm

32 3. Dekanhuset, Uppsala

36 4. Gamla gymnasiet, Karlstad

42 5. Ladugården, Biskops Arnö

46 6. Landshövdingens stall, Uppsala

49 7. Södra Banco, Gamla Stan, Stockholm

54 8. Thielska galleriet, Djurgården, Stockholm

58 Glossary


The building is unique and the art at Thielska galleriet, on Djurgården in Stockholm, requires a certain climate to prevent damage. The ambition has been to maintain the old ventilation system and complement it with installations that do not affect the architecture of the building.


Ventilation in a building is a fundamental func-tion. Preserving a culturally historic and valu-able environment at the same time as providing accepta ble ventilation for the tenant requires a great deal of experience and knowledge. This doc-ument has been drawn up to compile and share the knowledge regarding ventilation in historic buildings, which is currently held by the National Property Board Sweden (SFV). This knowledge is exemplified by general chapters on the history of ventilation, provisions and legislative protection, ventilation principles and good advice on main-

tenance and the design stage. In addition, eight examples are presented of venti lation solutions implemented in historically valuable environ-ments.

Through common understanding and compe-tence improvement measures, SFV s internal work with maintenance and renovation of culturally historical valuable buildings is facilitated and made more effective. These guidelines shall be able to function as a tool and inspiration for SFV as a property manager and building owner and for those consultants that SFV engages.

In preparing this document we have had the support of a reference group compiled of property managers, technical and operational managers and building conservation officers within SFV as well as the cultural heritage unit with all its specialist competences.

Property managers, project managers, and operation technicians have contributed with factual documentation and experiences from ref-erence objects. In addition, consulting engineer HVAC, Göran Stålbom, has parti cipated in the chapter Swedish regulations regarding ventilation and the chapter Ventilation history.

Stockholm, 20090429Carl Gösta Hellgren, HVAC specialist, SFVHelena Adolphson, architect

Ventilation – a conservation concern!In modern times, ventilation has often only been seen as a technical function. The effort to create the perfect indoor climate, which will function with a minimum of effort by the users, has led to increasingly bulky installations and technically complicated systems. Making use of the design of the building, which is a part of the ventilation sys-tem in historic buildings, has been neglected.

The original ventilation system is not only a function but also an expression of the building’s authenticity and character worthy of preservation.

Foreword

Stairway with heating column in the Gamla riksarkivet on Riddarholmen in Stockholm.


Ventilation historyDomestic buildings

In order to improve the stack effect it was possible to fit chim-neys with a cowl. It moves according to wind direction and creates negative pressure in the flue.

Moveable panes in both the outer and inner window case-ment. By making a small casement within the casement you could easily obtain ventilation without needing to open the entire window. Oxenstiernska palatset.

Open fireplacesVentilation and heating are often connected. Fires in ovens, tiled stoves and iron stoves create negative pressure in the building and an upward air stream in the flue – the stack effect. Replace-ment air is drawn in through leaks in walls, doors and windows and creates background ventilation. The hearth and its smoke flues have therefore, in older times, been sufficient during the winter to create the natural ventilation that is required. With open fireplaces and unsealed windows and doors, draughts were the major problem, not the actual ventilation. During summer, when the buildings were not heated by fire, the stack effect decreased. Ventilation was then done by opening windows.

In the 1700s and 1800s, windows were fitted with fixed inner casements in the winter. One pane in every room was able to be opened; a moveable pane. When coupled window casements were introduced at the end of the 1800s, the windows were often designed with transoms and separate upper casements for ventilation.


Radiator heat and stack ventilation From the 1920s, new buildings had radiator systems and bathrooms. Older buildings were restored with bathrooms and central heating. At this time, the majority of buildings were deep, as opposed to the narrow buildings that were constructed later on with modernism. Therefore, bathrooms were situated in the dark cores of the buildings. To ventilate these, a form of stack ventilation, so called Stockholm ventilation, was developed. The principle is that the bathroom has separate ducts for intake air and exhaust air. The air from the bathroom rises thermally, due to the stack effect, out through exhaust air vents near the ceiling via a brick flue in a chimney and out of the building. The intake air (replacement air) is drawn from the ground floor on the shady side of the building into the bathroom via a duct or a brick flue. In the winter, the stack effect is easiest to achieve, but this form of ventilation also works in the summer. During summer, the top of flue in the chimney stack is warmer than the duct for the intake air on the shady side of the building. This creates negative pressure in the flue, which speeds up the air flow out of the building and cool replacement air is drawn into the bathroom. The

From the 1920s, open fires were replaced by radiator systems with radiators below the windows. Areas near the external walls, which had previously been draughty and cold and had been used as passageways, now became warmer and were used as social areas. For intake air via windows, people have to be aware when placing furniture that there is a risk for draughts in areas close to the windows, even if it is heated.Oxenstiernska palatset, Stockholm.

Flap vent from Ahsell & Bernström’s cata-logue no. 32. This type of vent located in the external wall was often used dur-ing the 1800s and early 1900s to take in outside air.

Disc valve Disco from Rylander & Asplund’s catalogue no. 36. Commonly used as an intake vent in so-called Stockholm ventilation.


apartment’s kitchens and living areas had their own exhaust air flues and intake air via windows and vents in the external walls.

Low pressure systemsIn the 1930s, ceiling heights were reduced at the same time that fan ventilation was established. These early exhaust air systems existed parallel with stack ventilation up to the 1960s. The air was normally drawn in through slotted vents below windows. In 1931, the so-called overflow method was launched and has been used since then. This involves the air streaming in the “right way”: from bedrooms and the living room to the bathroom and kitchen. In that way a more efficient use of air was achieved. The ducts were often constructed of sheet metal but could also be made of mortar, concrete or asbestos cement. After the 1960s, sheet metal ducts dominated.

Controlled ventilationOlder fan systems had axial fans and disc valves with low pressure. In the early 1940 s, Svenska fläktfabriken launched a system with radial fans with higher pressure and so-called control valves that made possible a higher fall of pressure with-out sound problems. The advantage was that the ductwork could be made simpler and you could adjust the airflow with a higher degree of preci-sion. The outside air was drawn in via slotted vents beneath windows.

Supply and exhaust air systemsSystems with both supply air and exhaust air were installed in a number of apartment buildings in the early 1970s. However, it was first with the en-ergy provisions of the 1975 and 1980, a result of the oil crisis in the 1970s, that this had an impact. Through the supply and exhaust air systems with heat exchange the standard requirements for heat recovery could easily be attained. But as early as the 1980s there were objections to the systems

Slotted vents beneath a window seat; common from the 1930 s.

(based on maintenance problems and high operat-ing costs), and a search for alternatives started.

Return to the exhaust air systemAt the end of the 1980s, it was recommended by housing companies to only use exhaust air systems in newly constructed housing. For re-covery, a heat pump was used to heat hot water. Intake-air radiators, where the air was filtered and pre-heated, were often used for intake air.

Control valve KGD with attachment frame. From Svenska fläktfabriken’s Catalogue from 1963.


Ventilation historyNon-domestic buildings

Open fireplacesOffices, schools, hospitals, etc., were heated and ventilated in ways similar to residential housing. In prisons and mental institutions a central heat-ing system was desired to avoid dealing with fire in the premises.

Iron stove ventilationIn the 1860s a new system for ventilation was launched where the driving forces of the fireplace was utilized to get pre-heated air and increased ventilation. The manufacturers marketed special iron stoves and tiled stoves for this purpose. Cool outdoor air was conveyed from an insulated duct and let in at the bottom of the iron stove. The air was warmed and let out the top of the iron stove. The room’s exhaust air vent, located near the floor, was connected to a flue that ran next to the smoke flue. In this way, the exhaust air flue was heated for efficient air-flow.

Calorifère systemsCalorifère systems made their appearance in the latter part of the 1800s up through around 1910. They were central systems for both ventilation and heating and primarily used in school buildings, churches, barracks and hospitals. The outdoor air was drawn into a heat chamber in the cellar and then forwarded through separate ducts to each room. Sometimes the Calorifère systems had a complicated network of mortared ducts in order to make possible different oper ation scenarios. When central heating, in the form of radiator systems from the 1920s, became a standard solu-tion for new construction, the Calorifère systems

Before radiators were introduced in the form that we are now familiar with, they were designed in different styles. Here in Gamla riksarkivet on Riddarholmen they are designed as col-umns. In addition, some of these columns were provided with external air, conveyed via the joisted floors into the bottom of the radiator. The heated air rose upward and out the top of the radiator. Gamla riks arkivet, Stockholm


disappeared along with their double function for heating and ventilation. Individual Calorifère sys-tems can still be found, for example, in Thielska galleriet on Djurgården. They can also be found in new constructions with systems with heat cham-bers for the warming of intake air for example in Ladugården, Biskops Arnö and the exhibition pa-vilion at Birka.

Radiator heating and stack ventilationWhen central heating became predominant, exhaust air ventilation was solved with the help of the stack effect in brick flues. Intake air was drawn in via flap-vents in the external walls and through leaks in doors and windows.

Low pressure systems and early supply and exhaust air systemsIn the 1930s, a system was developed with sepa-rate supply and exhaust air ducts. Supply air devices were often located in the false ceiling in the middle of office spaces or in the “back cor-ner” by the ceiling in the wall facing the corridor. There was also a system where the air was sup-plied through a perforated false ceiling. From the 1960s, the system with supply air became much more common in offices, schools, etc.

Climate systemsAfter 1975, climate systems were often provided with comfort cooling. The function of the systems was to remove surplus heat. Sometimes the heat-ing system was integrated into the ventilation system; heating was done using air. The systems became increasingly advanced. One system that was developed in the 1960s was the dual-duct system: two supply air systems distributed air at different temperatures and the air was mixed to a suitable blast air injection temperature in each room. During the 1980s, the low-flow system with fan convectors (fan coils) placed in rooms became common. During the 1990s, the cooling-baffle (chilled beam) system was developed, first as

Thielska galleriet, in Stockholm, has an original Calorifère sys-tem. The radiators in the heat chamber pre-heat the intake air.

These fan convectors, so-called fan coils, have a single fan assisted batteries providing either chilled or heated air, as required by the room temperature controls.


As an alternative or complement to stack ventilation there are automatic window opening systems. These are computer-control-led and regulated based on ventilation needs. Vaxholms kastell.

Cooling baffles located near the ceiling. The air is cooled and falls down into the room.

separate cooling batteries with their own convec-tion, but relatively soon as integrated devices with both cooling batteries and supply air devices. In the early 2000s, interest for Variable Air Volume (VAV) systems has increased, in other words, sys-tems that utilize a varying air flow to govern the cooling effect.

Simpler systemsAt the end of the 1980s, protests were raised by those who considered that the systems had be-come increasingly space intensive and complex. A return to simpler systems was proposed and from the end of the 1990s a great many systems were installed that combined stack ventilation and fan ventilation, so-called hybrid ventilation. Solutions with automatic window opening sys-tems were also tested.


What laws apply?The Planning and Building Act (PBL) and the Act on Technical Requirements for Construction Works (BVL) are usually jointly referred to as building legislation. They apply to all construc-tion. Requirements are normally made on the property owner and apply to the building’s techni-cal characteristics.

The Environmental Code and Work Environment Act place no requirements on the actual building. Instead, requirements are placed on the environ-ment or work environment, which exists in the building. The requirements are primarily directed towards “persons operating a business” and the “employer”, normally the tenant. However, certain requirements are directed towards the property owner.

The laws make demands on ventilation, but this does not mean that you can carry out any measures or additions you wish. PBL requires that care shall be taken in the alteration of all buildings. The Environmental Code requires that valuable cultural environments are protected and preserved. Certain buildings are also protected by the Heritage Conservation Act.

Therefore, in every individual case a solution must be found that fulfils both the requirements for ventilation and the requirements for the pres-ervation of cultural value.

Requirement or recommendation?Society makes requirements through laws, ordi-nances and provisions. The professional primarily comes into contact with provisions and general recommendations, in which the authorities have clarified the legal requirements.

The provisions are mandatory, but the require-ments are often formulated in words as “nec-essary air exchange”, “good air quality” and “sufficient airflow”. As guidelines for the regula-tions, the authorities therefore issue general recommendations and handbooks with specific

values. The general recommendations provide recommendations about what you can or should do, but naturally do not exclude other measures. In individual cases an individual professional as-sessment must be made of what the provisions´ requirements on air exchange, air quality and comfort actually entail in practice.

Building legislationAll construction is governed by building legisla-tion. For new construction there are detailed pro-visions in the Building regulations (BBR) formulat-ed by the National Board of Housing, Building and Planning (Boverket). For alterations (renovations) there are no provisions. The alteration recommen-dations (BÄR), formulated by Boverket, only con-tain general recommendations. BÄR emphasizes a “careful comprehensive view” and leaves open-ings for ventilation solutions other than those re-quired by BBR. In works to older buildings it is wrong to routinely comply with BBR.

As a complement to the provisions, Boverket gives guidelines in the handbook Stack ventilation from 1994 and the Swedish Building Centre (Svensk

Swedish regulations regarding ventilation

12 pt12 pt

Differences between provisions and general recommendations

Issued by:

The Swedish Parliament

The Government

Central government authorities

Not

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M

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Statutes

Regulations

Ordinances

Laws

Provisions

General recommendations

Source: Göran Stålbom


byggtjänst) publishes Construction guidelines 15 – Renovation, 2000 and Construction guidelines 7 – Ventilation, 2008. Here, there are a number of guidelines regarding stack ventilation and fan-assisted stack ventilation.

For building alterations, BÄR applies. For on-going management you go directly to BVL, which says that facilities for ventilation shall “be main-tained”. To ensure that this is done, this is regularly checked through function inspections of the venti-lation system, (OVK). The professional assess-ment in individual cases is thus the responsibility of the function inspector.

Function inspection of ventilation systems (OVK)The ordinance regarding function inspections (1991:1273) shall ensure that all buildings, both new and old, shall have a satisfactory indoor climate.

The function inspection shall occur before a new ventilation system is put into operation the first time (first inspection). Existing systems shall be inspected regularly in accordance with the prescribed time interval.

Work Environment ActThe requirements in the Work Environment Act primarily relate to workplaces and schools. The Swedish Work Environment Authority issues regulations and general recommendations in order to clarify the requirements, and regulations regarding ventilation can be found mainly in Work-place design (Arbetsplatsens utformning – AFS2000:42). In these general recommendations there are several guidelines for air exchange.

It is often difficult to complement older build-ings with the same type of fan ventilation as new buildings. Therefore, there is a special provision

Skridskopaviljongen at Kastellholmen in Stockholm is being converted into a conference facility and is getting a ventila-tion system that is adapted to the building’s historic value.


Laws

• Planning and Building Act (PBL).

• Act on Technical Requirements for Construction

Works (BVL).

• Work Environment Act.

• Environmental code.

• Heritage Conservation Act.

Other regulations and regulatory frameworks

• General recommendations regarding alterations

to buildings, BÄR, the National Board of Housing,

Building and Planning, 2006.

• Regulations for function inspections of ventila-

tion systems, OVK, the National Board of

Housing, Building and Planning, 2008.

• Workplace design, Swedish Work Environment

Authority, 2000.

• The National Board of Health and Welfare’s

general recommendations regarding super-

vision in accordance with the Environmental

code – ventilation, 1999.

for “older buildings with historic value” in AFS 2000:42. It states, among other things that:

To avoid unnecessary measures to the building, special care should be given to the selection of technical solutions in the application of the pro-visions. When measures are necessary in order to achieve an acceptable work environment a measure should be chosen that involves the least possible damage to the historic value.

Therefore, in individual cases, a thorough balance must be made. As an alternative to increased air flow, for example, the general recommendations state “shorter work sessions with intermittent opening of windows”.

Environmental CodeThe Environmental Code mainly applies to residences, preschools and premises where the public has access. The Environmental Code’s re-quirement for ventilation is primarily detailed in the general recommendations that are issued by the National Board of Health and Welfare. There you can find guidelines for air exchange (similar to those of the Work Environment Authority). But the recommendations also emphasize ventilation possibilities, length of stay and procedures for ventilation.

The National Board of Health and Welfare’s general recommendations call for a comprehen-sive assessment of the conditions of the build-ings or premises for the operation concerned. The National Board of Health and Welfare does not state anything about buildings of cultural value, but one of the principles in the Environ-mental Code is the protection and preservation of valuable natural and cultural environments.

The Environmental Code’s requirement for protection and preservation of valuable cultural environments shall be assessed on a case by case basis in accordance with its requirements for in-door environments.

The official residences, “Långa raden”, on Skeppsholmen in Stockholm, originally built as barracks for Karl XII’s body-guards, is now being renovated into a hotel. A modern venti-lation system adapted to the building is being installed.


Protected buildings and building areasBuildings, parks and other facilities, land areas, city centres and other cultural environments that are a part of our Swedish cultural heritage are pro-tected through a series of different provisions at the governmental and municipal level. Those that are particularly significant can become listed his-toric buildings. Buildings that are not significant in themselves can also be included in this protec-tion if the entire building area, where they are lo-cated, is classified as a conservation area.

Ordinance (1988:1229) regarding historic state-owned listed buildings, FSBMThe Government decides if a state-owned build-ing shall be listed, SBM, after proposals from the Swedish National Heritage Board (RAÄ), which is the super visory authority that establishes protec-tion orders for the building. A somewhat lower protection class is valuable building and valuable property in accordance with FSBM § 12–16. Con-sultation takes place with the Swedish National Heritage Board for these in the case of measures that may threaten the historic value.

Heritage Conservation Act (1988:950), KLMBuildings of cultural-historical importance that are not listed in accordance with FSBM may be listed by the county administrative boards, which are responsible for formulating protection orders for the listed buildings in cooperation with the owner. Chapter 2 of the KML legislation addresses ques-tions regarding ancient and historic monuments and sites. In many older cities, entire city centres are designated as conservation areas where measures may require authorization by the county administrative boards.

Planning and Building Act (1987:10), PBLThe Planning and Building Act, chapter 3 § 10–12 states that all alter ations to buildings should al-ways be carried out carefully so that, for example, architectonic and historic values are safeguarded. Especially valuable buildings are protected in detailed plans and area provisions. The munici-pality is the supervisory authority in accordance with the Planning and Building Act.

Environmental Code (1998:808), MBThe Environmental Code covers areas that are of nationwide interest from a cultural perspective. Major measures may require an Environmental Impact Assessment.

Protection orders and authorizationThe protection orders for state-owned listed build-ings, formulated by the Swedish National Heritage Board and determined by the Government, define the values that are protected. In the protection orders it is stated what parts of the building that are specially protected. Authorization always must be obtained from the Swedish National Heritage Board for alterations that conflict with protection orders before any alterations may be made. Drilling in walls and joisted floors for venti-lation ducts or the mounting of new fans on roofs are examples of meaures that require authoriza-

Swedish legislative protection for historic buildings

Authorization from the Swedish National Heritage Board is required for drilling in existing brickwork. Skridskopaviljongen, Kastellholmen in Stockholm.


tion. Authorization for alterations to all other listed buildings must be obtained from the county administrative boards.

Conservation planSFV has decided that every state-owned listed building shall have its own conservation plan. It describes the building’s value and SFV’s long-term goal for the conservation and development of the building. The conservation plan gives recommendations and guidelines for the build-ing’s future management.

There is no legislation requiring conservation plans for other listed buildings. Nevertheless, the county administrative boards actively work to ensure that such plans are drawn up and grant subsidies to property owners for this.

Installation projectsConsequently, for installation projects, measures to protected parts must be approved by the Swedish National Heritage Board or the county administrative boards. Consideration must also be given to the legal text in the Planning and Building Act, which states that alterations shall be carried out carefully so that the building’s characteristics are taken into consideration. It can be very useful to let a conservation officer do a conservation assessment early in the design stage.

Measures to building foundations, for example when constructing new lift shafts, reinforcing foundations or laying new sewage pipes, may in some cases, especially in older city districts, require an excavation permit in accordance with provisions regarding conservation areas that are included in KML, chapter 2 (1988:950). In addition, shafts in the ground, for example for the installation of radon wells, can also require authorization.

Remains from the original facility for air heating shall be left untouched. Damaged wooden beams in the double flooring are replaced and a new wood floor has been installed. Skridskopaviljongen, Kastellholmen.

Concrete casting under the threshold is not a solution that the Swedish National Heritage Board recommends in a build-ing with wooden beams. The measure was, however, consid-ered necessary in this case and required an authorization. Skridskopaviljongen, Kastellholmen.


Stack ventilation systemStack ventilated buildings are constructed in such a way that the ventilation is promoted by the design of the building. In older buildings, which were originally constructed with this sys-tem, the exhaust air ducts were made of brick and served as both exhaust air flues and smoke flues for fireplaces. Due to the stack effect – warm air is lighter than cold air – the exhaust air rises thermally up and out of the building. The greater the difference in temperature between indoor and outdoor air, the more effective the stack effect. Outdoor air (replacement air) is drawn in through openings and leakage in windows and walls. The building’s design, for example large room volumes and rooms opening into one an-other in an enfilade, also contributes to good air exchange. In summer, when the stack effect de-creases, it is possible to create cross-ventilation by opening windows.

Exhaust air systemsWith the help of exhaust air fans, the exhaust air flow is regulated and ensured year-round. In older buildings, existing brick flues can often be used for exhaust air. Outdoor air is drawn in via openings and leaks in windows and walls, exactly as with stack ventilation.

Supply and exhaust air systemsThese systems have fans for intake air and ex-haust air. Through that, the volume of supply and exhaust air is regulated (balanced) and the risk for draught is reduced. These systems require advanced control equipment. Heat recovery can be arranged with the help of a heat exchanger that transfers the exhaust air’s heat to the supply air. For conservation reasons, the possibilities might be limited to running new ductwork. Existing brick flues can often be used for exhaust air and some-times even for supply air. Stairways and corridors

Ventilation principles

enkel systemskiss.

Stack ventilation systemExhaust air

Intake air

Exhaust air system

Intake air

Exhaust airFan

Supply and exhaust air systemIntake air Exhaust air

Ventilation unit

Supply air com-ponents:Damper, filter, heat exchanger,heat battery and fan

Exhaust air com-ponents:filter, heat exchanger, fan and damper


can sometimes be utilized as supply air ducts if the building’s layout and openness allows. Trans-ferred air to rooms with closed doors can be arranged with a transfer air device or recessing in thresholds.

CalorifèresThe calorifère system is an older system intended for both ventilation and heating, based on stack ventilation. Outdoor air is drawn, through the stack effect, into a heat chamber situated on the lower level of the building. There, the air is pre-heated during the winter. To regulate the air flow and temperature to the different rooms on the floors above, there are hatches at different heights in the brick ducts through which air is allocated. The rooms have intake and exhaust air vents at different heights. In the winter, the air is fed to the ceiling and drawn out by the floor. In this way the entire room is heated. In summer, the top of the chimney is heated by the sun. The flues therefore become warmer at the top than at the bottom, which increases the stack effect. The exhaust air rises out near the ceiling and the cool outdoor air from the heat chamber is carried along the floor. These systems are not automated and therefore require a great deal of knowledge and commitment from the property caretaker.

Hybrid ventilationWhen you combine different ventilation principles and create a unique combination, this is usually called hybrid ventilation. It is common to combine mechanical ventilation and natural ventilation and utilize the best of both systems. In summer when the stack effect is insufficient, fans are used for ventilation. When the outdoor temperature falls, the exhaust air fans can be shut down and stack ventilation functions. This is conditional upon the selected fans have very little resistance when

turned off. The system requires thorough adjust-ment. There are also developed systems with automatic opening of windows, controlled by the room climate and weather conditions. Here, the outdoor temperature and wind conditions are uti-lized to create a good indoor climate.

Calorifères

Hybrid ventilation

Exhaust air

Intake air

Exhaust air

Intake air

Ventilating via automatic win-dow opening systems

Heat chamber

Fan


Design stage

Survey of the building’s design and existing ventilation systemA survey of the existing ventilation system must be carried out; is it original? Does the building s design (layout, function, fabric etc.) constitute a part of the system? Can the system be restored? Will cleaning be sufficient? Can new technology that does not require visible installations comple-ment the system to improve performance? What are the brief requirements? Is the present tenant satisfied with the current ventilation? Can the ventilation meet the proposed tenant’s breif re-quirements? Cooling requirements, increased air flow? If needed, is there a possibility to run ducts and install a ventilation plant? Perhaps the build-ing already has a false ceiling and sufficient shaft areas. A conservation officer must be consulted. Studying the conservation plan to see what is per-mitted and doing a conservation assessment can be of great help.

Locating of existing brick fluesIf the building’s cultural value is so great that the possibility of running ducts is restricted, this affects the system choice and also the achievable indoor climate. If the system selection includes existing brick flues, these must be found and surveyed at an early stage, perhaps in occupied office spaces. Old drawings can sometimes give an indication of where the flues are. With the help of these, the survey can be done on-site. Smoke cartridges can be used to identify the flues in the chimney. The survey can then normally continue with the help of plumb lines. Radio detectors can also be used to find the flues in the walls. It is im-portant that flue survey is carried out at an early stage in order to avoid surprises in the construc-tion stage.

Original drawings showing chimney placement can be of help in locating the flues. Here, we see a part of the floor plan for Hårleman s extension to Södra Banco from the 1700s.

Good advice

Gamla Riksarkivet in Stockholm has an interesting ventilation and heating system. Room air is heated through circulation in heating columns. The air is taken in at the bottom and released as heated air from the top. The building’s exhaust air grilles are located near the floor. In this way, the cooler air is drawn out and warm air close to the ceiling is drawn downwards in the room.


Measures in existing brick fluesTo assess the status of the flues, possible air flow as well as tightness to maintain fire compartmen-tation in the building, CCTV-survey (filming) and gastightness test may be options. The flues must often be sealed with mortar or ceramic compound. There are different types of ceramic compounds and some of these contain chamotte (grog) as ballast with fibreglass reinforcement. Other com-pounds have pumice stone as ballast. Insertion of a rigid or flexible flue liner can sometimes be an alternative. Another technique is to insert a soft flexible tube of composite material into the flue from the top down. By inflating steam it gets its final form following that of the flue and heat treatment makes it irreversibly hardened. The ad-vantage of this method is that damaged flues are made tight and can be used as smoke flues at the same time as the maximum flue dimensions are maintained. The disadvantage is that you add new materials into the building that are not authentic. Sealing flues with mortar is totally in accordance with conservation thinking. Insertion of a rigid or flexible flue liner is a reversible solution. However, you must remember that the flue dimensions will reduce. When fitting old chimneys with axial fans, it is important to renovate the entire length of the flue, including above the fan. Otherwise, there is a risk that decayed mortar will fall down and stop the fan. Chimney tops must be equipped with a net to hinder birds from nesting in them.

Choice of consultantThe consultant must have understanding for and knowledge about the building’s character and qualities. He must have a sensitivity and desire to preserve older buildings. Provisions shall be followed but not over-interpreted. In addition, creativity is required in order to take into consid-eration the building’s design and characteristics in the choice of system. References from similar assignments must be shown.

CCTV-survey (filming) of brick flues from the roof of the Skridskopaviljongen, Kastellholmen, prior to a renovation of the building and its ventilation system.

Renovation of the brick flues was only done up to the height of the new axial fans at Södra Banco. No renovation was done from the flues upward and sometimes old mortar falls down into the fans and causes stops in the operation.

Things to remember

during the design stage

• Survey

• Consultation with a conservation officer

• Climate calculation

• Tenant requirements

• LCC-calculation


Relationship between the building s design and the operational requirementsProspective tenants should be informed about the special characteristics of the building and its role in the Swedish cultural heritage. Indoor climate calculations must often be carried out on alternative systems and compared with the brief requirement; sometimes a discussion must take place with the tenant in order to modify the re-quirement. Information must be given as to what will be required of the tenant so that the ventila-tion will function optimally. It may even be so that the climate that can be achieved in the building restricts the choice of operations.

Intake air via windowsIf mechanical supply air is not an option, the choice for the supply of outdoor air is often via trickle ventilators in the window casement or frame. A simpler solution that provides more intake air and does not damage the window is to avoid draught strips on the upper member of the casement-frame. The tolerance that a window must have between casement and frame in order to be opened properly often provides sufficient air flow. In selecting the method of supplying outdoor air, consideration must be given to the outdoor air’s level of purity and the risk of soiling.

Another principle is to utilize the space between the inner and outer window casements for the in-take of replacement air, which is then pre-heated. This requires constant negative pressure, in other words, mechanical exhaust air. In stack ventilated buildings there is a risk that the air will go out the wrong way between the panes and create condensation.

Flow measurements that have been carried out show that the natural gap between the upper casement and frame provides more intake air than trickle ventilators. Draught strips can be placed on other parts of the window to reduce draughts. Skridskopaviljongen, Kastellholmen.

Norra Banco’s windows do not have connected casements. Therefore, the trickle ventilators are fitted to the inner case-ments. The outer casements have no draught strips.


One cause of condensation between the casements can be that the gap between the outer and inner casements has been painted shut. Another cause can be that the room is not venti-lated in the right way and instead, air is drawn out via the closed windows.

Taking in outdoor air via grilles in the facade below the win-dow ledges into the radiators is a technically good solution. The air is pre-heated and also purified if you have filters in the folding radiators. Whether the solution is possible to carry out is mainly a conservation issue.

Vent convectors can provide pre-heated outdoor air when needed.

Making a survey of the presence of ground radon and carrying out the necessary measures is important. In buildings with mechanical exhaust air or stack ventilation, negative pressure is cre-ated that can result in ground radon being drawn in via air intakes and unsealed foundations.

To avoid intake air via windows being experi-enced as an unpleasant draught, it is important to inform the tenant that the furniture should not be placed too close to the windows. In older buildings there were often enfilade of rooms with passage areas close to the external walls and fur-nishing areas inside the rooms where iron stoves and tiled stoves were located.

Intake air via external wallsIt is an advantage if you can pre-heat the intake air upon entry. One way is to convey outside air via an intake air radiator. The air is drawn in through the external wall, filtered and pre-heated when pass-ing out through the rear of the radiator to be dis-persed over the radiator. Another way is to use an intake air convector that consists of a heat battery where outside air is pre-heated. It also contains a filter. In order for service to be carried out, the arrangement of furniture must be adapted to this.


Energy efficiencyThe consulting group must ensure that the heat load and energy needs are the lowest possible. With exhaust air or stack ventilation it is often difficult to arrange for heat recovery since the possibilities to transfer the heat are limited. The heat that can be recovered from exhaust air is not sufficiently high-tempered to have any benefits in the radiator system. Exhaust air heat pumps are a possible solution but finding a location for them can be difficult in older buildings. In addition, they make conservation considerations more difficult in regard to the necessary pipe and duct runs. One way to limit the energy need is to control

operating times in consideration of working hours. It is also possible to govern the air flow when needed with the help of CO2-transmitters. With low-flow alternatives (stack ventilation or exhaust air systems) it must be remembered that the venti-lating of emissions and odours from new furniture and paint layers takes time. A separate ventilation period without tenants may be necessary.

Indoor climate coolingWe impact buildings with higher heat emission than before. The cause is lighting, computers and other technical equipment as well as more staff than the buildings were originally intended for. Many of our historical buildings are actually old residences intended for a small number of people. The primary task is to work with reducing the

Instead of installing climate cooling, it is possible to reduce solar heat gains by using external sun-screens. Automatically controlled awnings protect Södra Banco’s rooms from the heat of the sun. In this way, the sun’s rays are obstructed both before and after office hours.

When installing plant rooms in attics in older buildings, special solutions are often necessary to reconcile the work environment requirements with the building’s design.


heat load. If cooling is still needed in accordance with the climate calculation, sun-shading should be investigated as an alternative: automatically controlled awnings can often be the solution. From the 1800s onward, awnings were a common resource to lower the indoor temperature in the summer. Sometimes, for various reasons, it can be difficult to get people to consider this alterna-tive. Studies in old photo archives often show that buildings have had awnings during an earlier period. This is especially true of buildings in a city environment. In addition, modern awnings are more reliable than older models. Another way to cool a building is to ventilate it at night via natu-ral or mechanical ventilation. If the fabric of the building has sufficient thermal capacity, cooling prior to the forthcoming warm working day can be very effective. When fitting out a previously unfit-ted attic, it should be remembered that in such an environment air-conditioning is almost always required, which results in a larger plant space requirement and increased installation and oper-ating costs.

Re-utilisationIt can be difficult to find details, ventilation grilles, etc., that fit into the historical environment. Such

things are no longer manufactured. The far-sighted manager can save details from demolitions and renovations for later use. When complicated ven-tilation systems are installed in older buildings, there is usually a surplus of needless details, which often are thrown away. You have to keep your eyes open.

Procurement and construction stage

Choice of contractorThe choice of contractor is especially important for installations in listed buildings. For measures involving brick flues, survey, sealing, etc., a con-tractor who understands this type of work must

The contractor must understand the principles for ventilation facilities. If you are going to achieve stack ventilation in a duct, it must be installed at a rising angle. The photo shows a new duct that was installed horizontally, which was noted by the inspector.

Old ventilation grilles from demolitions should be saved for re-use.

Things to remember during the procurement and construction stage

• Choice of contractor

• Inspector

• As-built drawings

• Documentation entered into the conservation

plan


contractors involved. Ventilation facilities must be documented in the conservation plan.

Management stage

User instructionsUser instructions shall be formulated prior to the tenant moving in; the project manager can easily understand how ceiling fans and intake air radia-tors shall function and work together, but there are examples of staff sitting all summer sweating without understanding that it is allowed to open the windows. User instructions shall be posted in a suitable location and an inventory should be taken each year to ensure that all affected person-nel have knowledge of how the ventilation system works.

Follow-upWhen a renovation of a property has been carried out and the tenant has experienced the indoor cli-mate during a year (summer and winter weather), it is valuable to monitor the indoor climate. Does the ventilation system function as it should? Are the personnel satisfied? A performance inspec-tion and a user survey will provide the answers. There is probably no subject that can be perceived so differently by people as ventilation. In certain cases the solution can be simple: the climate in a room may be perfect for one person but not for an-other. Such problems can sometimes be solved by having people change rooms with each other.

Things to remember

during the management stage

• User instructions

• Review of system user knowledge

• Performance inspection

be engaged. Ventilation contractors can often only run ducts and put together fan systems. Chimney sweeps and bricklayers often have to be hired. For unconventional ventilation systems this involves choosing a contractor who is used to finding unconventional solutions so that the entire concept of the system is not lost. One piece of ad-vice is to engage the ventilation consultant as in-spector since that is the person who understands the system best.

Documentation of the contractDocumentation of the completed contract must be carried out. Certificates of selected materials and the film of the flue inspection etc. must be saved. Since the location of the flues in reality seldom is in accordance with drawings, making as-built drawings after measurement are especially impor-tant. This is often forgotten since there are many

In the conference rooms in older buildings there is not al-ways enough ventilation for long sittings. Breaks and the opening of doors and windows may be needed. Södra Banco.


Eight examples in Sweden:

Eight buildings in SFV’s property holdings have been selected here since they illustrate the differ-ent ways to improve ventilation in buildings that are historically valuable. The ventilation solutions represent different principles for air distribution. The solutions have been possible to implement while complying with conservation requirements. The buildings’ design, which is a part of the original ventilation system, has been utilized and consequently the buildings’ authenticity has been preserved.

1. Amiralitetshuset page 24–28Amiralitetshuset is located on Skeppsholmen in Stockholm. The building was constructed in the 1600s and has undergone several renovations over the centuries. During the latest renovation at the end of the 1990s, the building was fitted with a new exhaust air system.

2. Sjöreservens kasern page 29–31This building, from the early 1900s, is located on Skeppsholmen in Stockholm. It was used by the naval reserve, which was responsible for the mooring of military ships and the island’s fire de-partment operation. The building was renovated in the late 1990s and was fitted with a new supply and exhaust air system for the conference rooms. The other rooms were fitted with an exhaust air system.

3. Dekanhuset page 32–35Dekanhuset in Uppsala traces its roots back to medieval times. The building has been remodelled and renovated on several occasions. In the lat-est renovation in the early 2000s, a new supply and exhaust air system with heat recovery was installed.

4. Gamla gymnasiet page 36–41Gamla Gymnasiet in Karlstad is one of only a few high schools that existed in Sweden in the mid-1700s. The building underwent a renovation in the

early 2000s and was fitted with exhaust air fans and an automatic window opening system.

5. Ladugården page 42–45From the middle ages and forward, the island Arnö in Lake Mälaren, has been a strategic loca-tion for the church and Sweden’s sovereigns. The barn (Ladugården) is from the 1800s and was renovated in the late 1990s. The building is stack ventilated and fitted with exhaust air fans, utilized during summer.

6. Landshövdingens stall page 46–48Today, the fairyland museum, Pelle Svanslös Hus, is housed in a building in Uppsala, which was originally constructed in the early 1800s as a guest stable for the county governor’s visitors. The building underwent a renovation prior to being turned into a museum and was fitted with exhaust air fans that are in operation during the summer. Other seasons of the year, the building is stack ventilated.

7. Södra Banco page 49–53Södra Bancohuset in Stockholm is Europe’s oldest bank building. Since the mid-1600s, office opera-tions have been carried out here. In connection with the building’s foundation needing reinforce-ment, an interior renovation was carried out and the building’s ventilation system was renovated. The building’s original ventilation system and its design have been taken into consideration and complemented with new technology that does not affect the building’s authenticity. The result is a supply and exhaust air system combined with stack ventilation.

8. Thielska galleriet page 54–57On the eastern part of Djurgården in Stockholm, the financier Ernest Thiel erected a palace. It be-came an impressive building with a, at that time, modern ventilation system. The Calorifère system not only ventilated the building’s exhibition halls, but also contributed to heating during the winter.



HistoryConstruction of Amiralitetshuset, which is located on Skeppsholmen in Stockholm, began in 1647 and the building was first used in 1650. The archi-tect was most likely the Dutchman, Louis Gillis. Originally, the building housed the admiralty’s offices and meeting rooms, as well as a sail store on the top floor. Amiralitetshuset has undergone several renovations but the sandstone portal is original. In 1680, the Royal Swedish Navy relocated to Karlskrona and from the late 1600s, Amiralitets-huset was used as an archives. The archives were relocated in the 1750s and the building was converted into a granary and the exterior drasti-cally altered. From 1794, parts of the building were used as a barracks. Between 1844 and 1846, a major renovation and restoration were carried out by architect Fredrik Blom. The building was converted into a barracks and acquired its cur-rent external design, which reflects the building’s original appearance. However, the corner towers are new additions. In 1952, the building was refur-bished by architect Rudolf Cronstedt to serve as the offices for the East Coast Naval District Staff,

1. Amiralitetshuset

Owner

• TheRoyalSwedishNavy

• SwedishFortificationsAgency

• NationalPropertyBoardSweden

Tenants

The Royal Swedish Navy and state have used

the building for many different activities over

the years such as:

• Barracks

• Offices

• Sailstore

• Granary

• Accommodationforsicksoldiers

Amiralitetshuset on Skeppsholmen has undergone several renovations. The latest was carried out at the end of the 1990s.

Skeppsholmen, Stockholm


becoming once again Amiralitetshuset. It has been listed as a historic building since 1935.

RenovationOver the years, the building has had many differ-ent tenants and was in need of external renova-tion. The building also needed internal renovation in order to be leased for modern office operations. The renovation was carried out from 1996–98 and included the restoration of the facades to their 1850s appearance. Internally, a lift, an emergency stairway and modern services were installed. A new underground ventilation and heating plant room was built to the building’s western side on the slope facing the water.

Ventilation before the renovationThe building had stack ventilation with intake air via windows and vents in the external walls and exhaust air via brick flues in chimneys. During the 1950s, the building’s bathrooms had been fitted with mechanical exhaust air. The ventilation sys-tem did not work since the old brick flues were not tight and also partially clogged.

Conditions for renovation of the ventilation systemThe building has thick external walls made of stone and brick. The room volumes are spacious. Therefore the air exchange can be low comparedwith modern buildings, which often have lower ceiling heights and therefore, smaller room vol-umes. Installing air conditioning systems are not necessary in these kinds of buildings. By cooling the fabric of the building by night ventilation, the mean radiant temperature of the space is reduced, improving the thermal comfort the following day.

Providing all floors with a traditional, mechanical supply and exhaust air system was not possible due to the building’s protection orders. I nstead the existing brick flues were renovated and con-nected to an exhaust air fan.

State-owned listed building

The building has been listed as a state-owned

historic building since 1935 and is subject to

protection orders, which state that alterations

to the building’s structure may not be carried

out without the authorization of the Swedish

National Heritage Board.

The building with its enfilade of rooms have generous room volumes. The tiled stoves that remain in the building have been plugged. The flues are used for exhaust air.

Amiralitetshuset is located on the western side of Skepps-holmen, in the center of Stockholm.


Conservation principlesIn the renovation, the ambition was to restore the building’s room volumes and room relationships.Many modern, lighter internal walls, which were added to the building in the 1950s, were demol-ished and previously closed door openings in load-bearing walls were opened up. This recreated the enfilade of rooms and provides important air movements. The parts of the buildning that are most worthy of preservation are the external brick walls, the portal, stairway and the joisted floors. Despite the fact that the facade may not be al-tered, the Swedish National Heritage Board gave an exemption for drilling below the window ledges for intake air. The building’s old flues could be renovated and used for mechanical exhaust air. Authorization was granted to fit out the unfitted attic level for new meeting rooms.

Ventilation after renovationDuring the renovation, mechanical exhaust air ventilation was installed, serving all floors. In addition, mechanical supply and exhaust air ven-tilation was installed in the attic, with provision for a supplementary increase in the ventilation flow rate.

Intake airBehind every window radiator there are two holes with a diameter of 7 cm drilled diagonally through the external wall. On the facade, below the window ledges, discreet ventilation grilles are mounted. In that way, the outdoor air is pre-heated. The radiators are fitted with filters. To change these it is easy to fold out the radiators from the wall. The supply air unit for the attic level with meeting rooms is located in the heating plant room, which is located outside the building. The former boiler chimney is used as a supply air duct serving attic level.

When a radiator is folded away from the wall for a filter change, it is possible to see the intake air holes in the external wall.

The Swedish National Heritage Board gave authorization to drill air holes through the facade and install intake air grilles so outdoor air can flow in behind the rooms’ radiators.


The supply air devices in the meeting rooms in the attic get their air via a flue that was previously a boiler chimney.

Exhaust air The existing flues have been cleaned and tight-ened with plaster. Control valves have been mounted in the brick flues in each room. All brick flues are connected at the ridges in the attic with sheet metal ductwork that directs air down to the exhaust air fan, which is located in the attic. The exhaust air exits via the existing chimney.

ExperiencesA survey of the flues must be done at an early stage, preferably in the design stage. For this project, no survey was done; the work with the existing brick flues was started much too late; the offices were already renovated and painted. The old drawings that the project planning was based on were incorrect, which meant that new

Outdoor air is drawn in via holes in the facade behind the radiator, which pre-heates the air. The small photo shows the intake air grilles in the radiator in the closed position.

The exhaust air fan is located in the attic. The flues in the existing chimneys are connected in the ridged attic with horizontal sheet metal ducts that lead down to the exhaust air fan.


holes had to be drilled for vents. Consequently, the rooms had to be repainted. After the ten-ant had moved in there were complaints about draughts from the windows. The workplaces were positioned close to intake air radiators and this, in combination with the fact that the radiator temperature, for energy-saving reasons, had been lowered, made the incoming air feel cold. The ten-ant would then close the intake air vents in the ra-diators, which in turn caused the ventilation to be inadequate. In addition, the number of workplaces in every room had increased relative to what was planned for. With the right information to the

tenant and operating staff, these problems have been rectified. Informing the tenant about how the ventilation functions is essential.

Outline diagram, flows in Amiralitetshuset

Outdoor air is drawn in through grilles in the facade, is filtered and pre-heated in the radiator

The exhaust air fan on the top floor draws out the air through existing brick ducts

The supply air unit, which only serves the conference rooms in the attic, contains damper, filter, heat battery and fan


HistoryThis building was constructed in 1907 on the southeast side of the island Skeppsholmen as a barracks for the naval reserve, which was respon-sible for the mooring and dry-docking of military ships and for dealing with any fires that occurred on the docks.

RenovationThe barracks were renovated in 1997 for the National Property Board Sweden, which since that time has had one of its management offices there. The building, which is made of timber, had poorly insulated external walls. The suspended floor had rotted. This was rectified in the renovation. The external walls were further insulated and the joisted floors were renovated. A lift and a new cellar area containing a new heating plant and storage area were installed. The attic was fitted out as a staff room and conference room.

Ventilation before the renovationThe building was stack ventilated and had never had acceptable heating. Outdoor air was drawn into the building via slotted vents, from the mid-1930s, located below the window seats. The venti-lation did not function well.

2. Sjöreservens kasern

Owner

• TheRoyalSwedishNavy

• SwedishFortificationsAgancy


Tenants

The building has been used as a barracks, art

studio and currently serves as an office for the

National Property Board Sweden.

Sjöreservens kasern on Skeppsholmen, currently a local office for the National Property Board Sweden.

Skeppsholmen, Stockholm


Conditions for renovation of the ventilation systemThe building’s rooms had large volumes and the ventilation was designed accordingly. When a new operation was coming in, this required a new room layout in order to have many office spaces. This required enhanced air exchange. The high ceilings allowed false ceilings in the corridors. In connection with the additional insulation of the facade, it was easy to mount air intakes below the window ledges.

Conservation principlesThe entire island is a state-owned listed conserva-tion area. The exterior of Sjöreservens kasernis subject to protection orders. This meant that

there was no problem in renovating the building to a modern standard and installing a new ventila-tion system.

Ventilation after renovationThe building was fitted with mechanical exhaust air and air intake using intake air radiators. Since the building has a light timber frame, cooling was necessary. The meeting rooms, therefore, have mechanical supply air with cooling. The offices have been fitted with cooling baffles and ceiling fans that are controlled manually according to needs. In the summer, the ceiling fans, so-called Casablanca fans, help to disperse the cool air in the rooms. In the winter they force the warm air down, which would otherwise stay near the ceiling.

Intake airUnder every window there is an intake-air radiator; behind this the air is drawn in through slits in the facade. On the outside, the slits are covered by grilles placed just below the window ledges. The radiators are fitted with filters. To change these you can simply fold out the radiator from the wall. The large meeting room on the ground floor and the meeting room in the attic are provided with supply air via a unit placed in the attic. The sup-ply air unit has a rotating heat exchanger for heat recovery from the exhaust air. The air intake is lo-cated on the northern gable in order to obtain the coolest air possible.

State-owned listed historical building

The entire island Skeppsholmen is a state-

owned listed conservation area in accordance

with the Ordinance regarding state-owned listed

buildings since 1935 with a change in conserva-

tion status in 1993 and 1998. The exterior of the

building is subject to protection orders.

Air intake below the window ledge.

External air is drawn into the radiator, which is foldable and has a filter.


Outline diagram, flows in Sjöreservens kasern

Outdoor air is drawn in via grilles in the facade, filtered and pre-heated in each radiator

Air handling unit con-taining supply and exhaust air fans,filter, heat exchanger, heating and cooling bat-teries

Exhaust airThe building has been fitted with mechanical ex-haust air via ducts connected to a unit located in the attic. Heat in the exhaust air is recovered and added to the intake air via the heat exchanger. The air emission vent is located on the southern gable.

ExperiencesThe radiator temperature must be sufficiently high in order to be able to heat the intake air. User instructions are important for instructing people how to operate ceiling fans, cooling baffles, in-creased air flow and intake air radiators. Tenants should also be made aware that placing furniture near windows is not recommended. This is be-cause some people might experience draughts and also because the property caretaker must be able to easily change the filters in the radiators.

The offices have been fitted with ceiling fans. The fan has dif-ferent speed settings and reversible rotation settings. In the winter the fans help to push down the warm pillow of air near the ceiling. All workrooms and conference rooms have cooling baffles. In the summer, the ceiling fans circulate the cooled air in the rooms.

Here, you can see the exhaust air grille on the southern gable. The air intake is located on the northern gable for cooler air.

Ceiling fans help to even out room temperatures


HistoryThe building, called Dekanhuset, was given by the Bishop of Skara during his term of office as dean in Uppsala in the beginning of the 1300s to the Uppsala Free Deanery, now called diocese.The building is believed to have been destroyed in 1447 by fire, but a new building was erected on the old foundation five years later by the arch bishop at that time. In the mid-1700s the property was purchased by university treasurer, P. Julinskiöld. He rebuilt it to be the largest palatial

residence in Uppsala. At the end of the 1700s, the property was transferred to Uppsala University where it was used as both an apartment building and school. Today, elements from all epochs can be seen in Dekanhuset. A part of the cellar, from medieval times with its brick cross-vaults, is in-tact. Certain rooms still have interior decorations from the Julinskiöld Palace. The design of the facade and windows is from the early 1800s when the building was converted into a school. The formal hall with a double storey ceiling height is also from this time. The building is a state-owned listed building.

RenovationWhen SFV s tenant, the Faculty of Theology, moved out, a renovation was necessary. During an earlier renovation of the building, the old formal hall with a double storey ceiling height had been rebuilt as two stories. For this renovation it was decided to restore the double storey ceiling height of the formal hall.

3. Dekanhuset

Owner

• DeanandBishopofSkara,1300s

• UppsalaFreeDeanery,1326

• Universitytreasurer,P.Juhlinskiöld,1746–

1768

• UppsalaUniversity,1768–1830

• SwedishChurch


Tenants The building was initially used by the church

but was converted in the 1700s to a private

palace. After that, the building was used as

an apartment building and then renovated to

house various schools. Today, the building is

used for offices.

Dekanhuset, Uppsala. Presently the district office for SFV, division NO.

Uppsala


Ventilation before the renovationThe ventilation was adapted to the church s edu-cation premises, the Faculty of Theology. They had a mechanical supply and exhaust air unit that served the large teaching rooms. The small rooms had a poorly functioning stack ventilation.

Conditions for renovation of the ventilation systemSFV wanted to design the new ventilation system so that every floor could be able to be separated for different tenants if needed. When the formal hall was restored into its original double storey ceiling height, this resulted, however, in floors 3 and 4 becoming one fire compartment. It was also important that the new ventilation system should be modern and adapted to the building for preserving its unique character. Holes that were already made in the walls for the old mechanical ventilation system could be reused when install-ing the new system.

Conservation principlesThe building s medieval cellar, exterior, frame, room layout and purpose-built interior decorations are protected by the protection orders and must be left untouched to the greatest extent possible. Unavoidable holes have therefore, to the extent possible, been located to existing or previously filled holes. All installations have been car-ried out in such a way that they are reversible and easy to maintain and replace. A large new



historic building since 1935 and is since 1993

subject to protection orders, which state that

alterations to the building’s structure may not

be carried out without the authorization of the

Swedish National Heritage Board.

During this renovation of the old formal hall the original double storey ceiling height was restored.

Openable windows are still an appreciated complement to the mechanical ventilation in summer.


Supply air is distributed through purpose-built wood grat-ings, designed to fit in with the carpentry of the building.

opening was required in the joisted floors for the installation of a lift. At that time, a services shaft was constructed adjacent to the lift beside the stairway in the newest part of the building. Consequently, all the room volumes remained unaltered.

Ventilation after the renovationA mechanical supply and exhaust air system with heat recovery, which was adapted as much as possible to the building, was chosen. Water bat-teries in the exhaust air unit in the attic recover the heat in the exhaust air. The heated water is distributed via the services shaft to the supply air unit in the cellar. The supply air can also be cooled when needed by the use of groundwater. During summer the fabric of the building is cooled by night ventilation, i.e. night cooling. Fan coolers are located in several areas in the building and are placed in purpose-built benches or covers designed to look like tiled stoves.

Supply airThe space under the building consists of three parts. There is the original cellar from medieval times with cross-vaults that cannot be altered. Then there is an 18th century cellar that has been used as a heating plant room for some time. Between these there is an unexcavated area. A new supply air unit has been located in the 18th century cellar. The outside air comes from a newly built air inlet outside the building at ground level. The unit can distribute pre-heated or cooled air. Cold water is pumped in via a borehole and after the cooling is utilized, the heated water is pumped back into the ground via two other boreholes. The supply air ductwork is run through the unexcavat-ed part of the ground floor beneath the joists to a vertical services shaft located alongside the new toilet groups and storage areas.

The conference rooms and certain offices and corridors are fitted with purpose-built benches with fan coils. They provide either chilled or heated air, as required by the room tempera-ture controls.


Outline diagram, flows in Dekanhuset

Air intake via a hood located on the ground at the rear of the building

Supply air unit with cooling and heating of air

Supply air via a cen-trally located shaft

Exhaust air via existing brick flues

Exhaust air fan in the attic with heat recovery battery

Air inlet through a new hood at the rear of the building. Locating air inlets high up is best, but was not possible due to aesthetic reasons.

This new fan air-cooler has been designed to look like a tiled stove to fit in with the environment.

Exhaust airThe building had very good conditions for hidden exhaust air. All rooms had separate clay brick flues. They were cleaned and sealed. In the un-fitted attic, these flues could be connected by ducts to an exhaust air unit. The air is let out via previously built chimney-like exhaust air hoods on the roof. The exhaust air unit has a water battery for heat recovery that is connected to the supply air unit in the cellar for pre-heating the supply air when needed.

ExperiencesThrough the renovation, SFV s wish to get a ventilation system that could function for many different tenants was fulfilled. Utilizing the un-excavated area underneath the double flooring for running ductwork has been very successful. The entire building has a very effective and aesthetically appealing ventilation solution that offers the property owners the maximum flexibil-ity when leasing of premises. The current tenant is very satisfied with the system.


HistoryIn the middle of the 1700s there were only a few high schools in Sweden. In the Karlstad diocese there was an elementary school with education for high school proficiency. The school was made of timber and when it burned down in 1752 the church decided to construct a new high school with an observatory on the roof. The assignment was given to architect Carl Hårleman. He died in

1753 but left behind his signed drawings. When the construction of the building started, his col-league and successor, architect and director Carl Johan Cronstedt had revised and adapted the drawings. In 1754, construction of the high school was started. The building was completed in 1759. Architect Johan Eberhard Carlberg was respon-sible for the construction together with senior master, Johan Fryxell. Carlberg is named as the architect that designed Karlstad High School. The special stepped gables are attributed to him. The building has been a state-owned listed build-ing since 1935.

RenovationThe building has been renovated and altered onseveral occasions due to wear and tear, neglectedmaintenance and poor masonry. All major changes to the building were carried out before it was listed as a state-owned historic building. The most recent renovation was carried out in 2005–2006.

4. Gamla gymnasiet

Owner

The Swedish Church owned the property

until 1929 when it became the property of

the state. Since 1993 it has been owned by

the National Property Board Sweden.

Tenants

Over the years the building has housed

various operations and has been used as a

high school, field hospital, pharmacy,

for storing cultural and historical museum

collections, and administration for cathedral

chapters and the County Administrative Board.

Currently, the premises are used for offices

and museum and association operations.

Gamla gymnasiet in Karlstad, with the observatory on the roof.

Karlstad


Prästsalen (Priest s hall) with an automatic window opening system.

Ventilation before the renovationThe building was stack ventilated. The exhaust air rose out via tiled stoves with the help of tem-perature differences, the stack effect. Replace-ment air, (outdoor air), was drawn in through leakage between window frames and window casements. However, the ventilation did not function. The brick flues had not been cleaned and had cracks due to settlement damage. Some parts of the flues had disintegrated.

Conditions for renovation of the ventilation systemThe building was constructed using the build-ing techniques of the period, with thick stone and brick external walls and with large ceiling heights, which provide good conditions for stack ventilation during the part of the year when the outdoor air is cooler than the indoor air. During the summer months the stack effect decreases and with that, the exhaust air. The intention was to create a ventilation system that could function year-round. The attic and cellar have always been storage areas and would remain so, and there-fore did not require extra ventilation and cooling, which would otherwise be necessary in order to have workplaces there.








Outdoor air is drawn in via the gaps between the upper part of the window-casement and the window-frame, where there are no draught strips. The rest of the window has strips to prevent draught.


Conservation principlesAs a listed building, it is required that all walls remain intact. This means that new installations can not be hidden in the walls. The technical ad-ditions must then be designed so that the rooms retain their architectural character. SFV s cultural heritage unit proposed, at a very early stage in the design process, that the building s original ex-haust air flues should be restored. This, together with the engaged ventilation consultant proposing an automatic window opening system, made the conservation principles quite simple. The only internal ventilation additions were the motors con-trolling the automatic opening of certain window casements and the visible electrical and computer connections to these. The location of the motors, was an aesthetic conservation issue. The fact that this automatic window opening system actually was able to be used was due to the window case-ments having been replaced in the 1920s with coupled window casements, which were suitable for this solution. If the casements had been origi-nal from the 1700s things would have been differ-ent. 18th century casements can be very fragile and are not suited for this motorized window opening system.

Ventilation after the renovationThe natural ventilation system has been re-tained and developed. Air still comes in via gaps in the windows but certain rooms on the second floor have an automatic window opening system. Exhaust air still rises thermally through the old brick flues. Propeller fans were installed in the flues and are turned on when the stack effect ceases during the warm part of the year. In this way the building has a functioning exhaust air system year-round.

Since it was too costly to rebuild all the disintegrated brick flues some of them were repaired and fitted with flexible flue liners.

Since the old chimney stacks are not used anymore for fire, exhaust air grilles have been mounted directly in the flues above the tiled stoves.


Intake airReplacement air is drawn in via gaps between the upper part of the window-casement and the window-frame, where there are no draught strips.

Exhaust airAll exhaust air flues were made of brick (in chim-ney stacks) and in a very poor condition before the renovation. During the survey it was discovered that the flues had very restricted cross sectional areas. This meant that they could not provide the required air exchange for a good indoor climate. Since the brick flues were to be used for exhaust air they had to be renovated. It was possible to seal some flues with plaster. Other brick flues had partially disintegrated and were too costly to re-build. Therefore flexible flue liners were inserted, even though this results in a reduced cross sec-tional area. Initially, many exhaust air flues served more than just one room; sometimes rooms on other floors. This problem was unable to be solved and instead, attempts were made to minimize the number of shared flues and also ensure that no rooms on different floors were served by the same flue. Fire compartmentalizing in accordance with today s requirements could not be achieved and the entire building is one fire compartment. Axial fans (propeller fans) are installed on top of the chimneys. The fans ensure that the building has a background ventilation during the warmer part of the year (March through September), when the stack effect ceases. The fans are turned off in winter. They provide virtually no resistance when turned off and therefore, do not counteract the stack effect. The original exhaust air grilles have been kept to the extent possible but new ones were manufactured. Behind these grilles control valves are mounted. They are adjusted to provide the correct exhaust air flow since one fan serves all the flues in each chimney. Since the exhaust air flues only provide background ventilation, the exhaust air in certain rooms must be increased by cross-ventilation via an automatic window open-ing system.

The wet areas have separate exhaust air fans.

Control valves which are adjusted to provide the correct ex-haust air flow are located behind the exhaust air grilles.


Intake and exhaust air via automatic window opening systemsIn some parts of the building the possible rate of exhaust air via flues can not provide the acquired air exchange for the operation being carried out there. To compensate for this an automatic win-dow opening system has been installed. For every set of windows, one of the upper casements is equipped with a motor-controlled arm that can automatically open the window casement as much as is needed. The opening of the windows – how much and how long – is governed by carbon diox-ide meters that are placed in various zones in the building and also by the weather station on the roof. It has a meter for wind direction, wind veloci-

A motor for opening the window automatically is placed on the window’s transom. The electrical cord is visible along the window frame.

Outline diagram of the automatic window opening system. The sys-tem works well in rooms with windows facing in several directions.

Installations in Prästsalen

New motors for opening the win-dows automati-cally; 1 motor per window

Existing radiators


ty, rain and indoor and outdoor temperature. During the summer, cross-ventilation is done at night by the automatic window opening system for cooling the fabric of the building prior to the forthcoming, warm working days.

ExperiencesThe National Property Board Sweden had an in-terest in testing an automatic window opening system and the decision to do so has been very successful. The property s tenants are satis-fied with the ventilation. The air is perceived as pleasant. The tenants have no problem adapting to the building s conditions. In those rooms with automatic window opening, everyone knows to use paperweights for their papers due to the cross-ventilation. During the warm summer weeks, extra ventilation at night cools the build-ing. This, in combination with the building s very thick external walls, has helped to maintain a satisfactory indoor temperature even during ex-tremely hot summers. The thick brick walls assist night-time cooling, which evens out the daytime temperature. The purpose of the renovation of the building was to retain the original ventilation sys-tem and complement it with new technology – an automatic window opening system – which is not at variance with the conservation of the building. Consequently, for aesthetic reasons, external air is drawn in through natural gaps. No draught strips are used between the upper part of the window-casement and the window-frame.

Outline diagram, flows in Gamla gymnasiet in Karlstad

Air intake via gaps between the frame and casement on the upper edge of the window

Exhaust air via clay brick flues, through stack ventilation

The weather station on the roof controls the automatic window opening system with a meter for wind direction, wind velocity, rainfall and temperature.

Exhaust air fans in operation during the summer

Complements with auto-matic window opening system on the second floor


HistoryBiskops-Arnö is a small island in Lake Mälaren. It is located close to the mainland in the munici-pality of Håbo outside Enköping. The island has a long history as a cultural landscape with interesting buildings. In the 1280s the island was purchased by Uppsala Cathedral as a link in the church’s desire to have branches along the important waterways from Uppsala to the Baltic Sea. In 1325, work began with the construction of the castle, Arnöborg. Agricultural activities and livestock activities were carried out here and Upp-sala’s bishops were allowed to use the island as a residence and private summer place. Of the im-pressive castles, today there remains only a part of the cellar with its medieval brick vaults. New buildings for residences and farming have been constructed over time. In the 1700s a new main building with two wings was constructed, still pre-served today. The agricultural landscape with its flora and bird life is unique for Sweden.

RenovationWhen the folk high school needed to expand with more classrooms in the middle of the 1990s, Ladu-gården (the barn) from the 1800s (at that time va-cant) was utilized. Here, it was possible to have an effective lecture hall and computer rooms. There was also space for a photo lab and offices.

Ventilation before the renovationBefore the renovation, the barn had no special ventilation system. The building was ventilated through openings and leaks in walls and ceilings and by cross-ventilation.

Conditions for renovation of the ventilation systemWhat was desired was a ventilation system that was as simple as possible, cheap to install, not visible and easy to manage by the tenant.

Conservation principlesThe entire island is a state-owned listed con-servation area so it is important to preserve all

5. Ladugården

Owners

• 1200s:Birgerjarl’sson

• 1500s:GustavVasa

• 1600s:Swedishnobles

• 1700s:SwedishCrown

• 1800s:SwedishState

• Today:NationalPropertyBoardSweden

Tenants

The island has had many different tenants:

Uppsala’s bishops, Swedish Kings, including

Gustav Vasa and his family, noble families

and captains for the Royal Lifeguard Mounted

Regiment. Since 1956, the foundation, Nordens

Biskops-Arnö, has operated a folk high school

on the island.

The barn has been renovated to house classrooms. The build-ing has exterior protection orders and authorization was granted to complement the roof with ventilation hoods.

Biskops-Arnö




historic building since 1935 and is since 1993

subject to protection orders, which state that

alterations to the building’s exterior may not be

carried out without the authorization of the

Swedish National Heritage Board.

Intake air grilles in the facade. The former manure hatch has been cut in the lower edge. The gap is sufficiently large to provide air into the building even with the hatch closed.

An existing hatch that has been slightly opened is used as an air intake to the heat chamber (calorifère).

The air into the classrooms comes via vent convectors. The outdoor air can thus be pre-heated when needed.

buildings. The exterior of the building is subject to protection orders. This meant that during the renovation, external walls and the roof, to the extent possible, should not be altered. Existing hatches and doors have been utilized for outdoor air intakes without this being seen as an altera-tion. In the facade, the brick drainage pipes, which previously let air into the building, still remain. These have been internally sealed since they are no longer needed for air exchange. The building has an original reed roof, which was cov-ered with sheet metal in the mid-1900s. Since the reed roof was to be retained, the roof could not be insulated. Instead, roof insulation was laid in the joisted floor of the attic. Authorization was granted to complement the building with four exhaust air hoods in traditional barn style.


Ventilation after renovationThe building is stack ventilated and complemented with exhaust air fans, utilized during summer.

Intake airOutdoor air is drawn in via vent convectors, equipped with batteries for pre-heating. In gen-eral, cross-ventilation via opening windows, can easily be done in the summer. The large lecture hall also has ventilation and heating during the winter via a heat chamber, so-called calorifère.

Exhaust airThe air rises upward and out via three newly constructed air shafts with the help of the stack effect in the winter and fans in the summer. Each air shaft has an axial fan. The fans are controlled by timers that the tenant sets. There is a hatch at the bottom of every shaft, which by the use of a rope, can be set in different positions so that the desired air flow can be obtained. The bathrooms have their own mechanical exhaust air, which is on constantly. The photo lab also has a separate exhaust air fan that is automatically activated when the room is in use.

To get sufficient air exchange in the large assembly room, it is ventilated with a so-called calorifère system. In the photo you can see the intake air grates in the wall facing the heat chamber.

The large lecture hall is exhaust air ventilated by the newly constructed air shaft above the wood gratings in the ceiling.

The photo lab has a separate exhaust air fan, which is put into operation when needed.


Outline diagram, flows in Ladugården Biskops Arnö

Air intake via vent convectors

Air intake to the lecture hall via a heat chamber, so-called calorifère

Exhaust air via stack ventilation, which in the summer is fan-assisted

The air shaft viewed from underneath where the axial fan can be seen. With a rope, the hatch can be regulated to obtain the desired exhaust air flow, either via stack ventilation or fan.

The new exhaust air shafts as well as the attic joist floor are in-sulated. In this way, insulation of the roof was avoided, as it has protection orders and may not be altered.

In the inner part of this classroom there is an air shaft in the ceiling with an axial fan. The fan is started by the tenant when needed.

ExperiencesThe ventilation system meets all the function requirements that have been made. Course arrang-ers and course participants are very satisfied with the ventilation.


HistoryIn the early 1800s, this stable was constructed for the visitors of the county governor in Uppsala who came by horse and carriage. There was also space here for several cows. From the early 1900s the building has mostly been unused, but it has also been used as a storage place.

RenovationThe stable was in very bad condition before the renovation. It had not been maintained and was partially fire-damaged. When the National Prop-erty Board Sweden had found a suitable tenant, the renovation was initiated.

Ventilation before the renovationThis stable was exactly like the majority of other stables; without a heating and ventilation system.

6. Landshövdingens stall

Ventilation was done through cross-ventilation and gaps in walls, doors and windows.

Conditions for renovation of the ventilation systemWith a new operation in the building, another ven-tilation method was necessary. To comply with the property’s historic building status, the simplest type of ventilation system possible was preferred. This could make the renovation less expensive and still the tenant could easily ensure that the building would have an acceptable and suitable air exchange. Since the building has a heavy brick frame and high ceilings, stack ventilation is a good solution.

Welcome to Pelle Svanslös Hus.

Uppsala


Conservation principlesWhen the building was going to be renovated and get heating there was a problem due to the fact that the base of the roof was totally built together with the roof. Drilling holes in the base of the roof was not possible due to the protection orders. Since ventilation of the roof is absolutely neces-sary, the problem had to be solved in another way. Thanks to the fact that the roof had been renovated in modern times, autorization could be given to lift the entire roof truss to create a gap between the base of the roof and the facade. The building has never been furnished and the interior design was done in such a way that it is reversible. The building can easily be adapted to another tenant.








The building still has its original exterior with its transport bridge at the rear. The kitchen fan, on the far right, can in-crease the air flow when needed. Close by, you can see one of the buildings two bathroom fans. They are in operation 24-hours a day in the summer and during the museum’s open hours in the winter.

The fan can be turned on by the tenant when the stack effect is not sufficient, for example, when it is hot outside. When the fan is started, the hoods for the natural ventilation close automatically otherwise air is drawn in that way.

The building has two chimneys for stack ventilation with damp-ers that can be opened and closed as needed. The location and opening time of the dampers are regulated manually with a timer operated by the tenant when extra ventilation is needed. The dampers are closed automatically when the adjacent exhaust air fan is put into operation.

Owners

Always owned by the state. Since 1993,

National Property Board Sweden

Tenants

Stable operations ceased in the early 1900s

and after that the building was only used as

a storage space until the National Property

Board Sweden found a new operation, the

fairyland museum for the local celebrity,

Pelle Svanslös.


Ventilation after renovationThe building has stack ventilation. In the summer, when the stack effect is insufficient, exhaust air fans can be turned on when needed. Bathrooms and kitchens have exhaust air fans for continu-ous operation.

Intake airWindows and doors have trickle ventilators to achieve background ventilation. Air is also drawn in via vent convectors that provide pre-heating in the winter. Apart from that, ventilation is done by the tenant opening doors and windows.

Exhaust airThe two bathrooms and kitchen all have separate exhaust air ducts connected to fans on the roof for continuous operation. In general, the building has adjustable exhaust air that the tenant regulates. On the roof, there are two newly-built hoods that function as chimneys for stack ventilation with dampers that can be opened. The tenant controls the opening of the dampers with a timer. Also, there is an additional hood on the roof with an

exhaust air fan. It is also controlled by a timer. In this way, the tenant can choose to increase the exhaust air if needed.

ExperiencesThe ventilation system is simple to manage and the tenant has received oral and written instruc-tions. However, on hot summer days the heat can be extreme. Despite the fact that preparations for the installation of a cooling system have been made, the tenant does not think that it is neces-sary. Another way to cool the building would be to arrange increased air flow at night.

Outline diagram, flows in Landshövdingens stall

Outdoor air via trickle ventilators and cross-ventilation via opening windows and doors

Exhaust air via stack ventilation, which in the summer is complemented with an exhaust air fan

Background ventilation via bathrooms fans

It is necessary to continuously inform the tenant about how the ventilation is designed to work. Here, a piano has been placed in front of the intake air vent.


7. Södra Banco

HistoryIn the middle of the 1600s, the townsmen and council decided that a Bank of Sweden should be constructed adjacent to Järntorget in Gamla Stan (Old Town) in Stockholm. Architect, Nicodemus Tessin the elder was given the assignment to be responsible for the con struction of northern Europe s first banking building. The building was nearly completed in 1680 and the Bank of Sweden moved in. After that, construction continued and the building was completed in 1712, first by Tessin the elder and then his son, Tessin the younger. In 1730, architect Carl Hårleman, was commis-sioned to carry out an extension to the building, which was completed in 1737. The property then stretched from Järntorget down to Skeppsbron and has been used as offices ever since it was first built.








Owner

Always owned by the state. Today National

Property Board Sweden

Tenants

• TheBankofSweden1668–1906

• Museum,achivesandoffices

• NationalPropertyBoardSwedensince1994

The entrance hall to Södra Banco is open for the public.

Södra Banco has two court-yards.

Gamla Stan, Stockholm


Foundation reinforcement and renovation In 2003–2004, Södra Bancohuset underwent extensive foundation reinforcement. The tenant, SFV, had to move out during this time. A major reinforcement operation of the foundation and masonry work from the 17th and 18th centuries was required to stabilise the building. In 2004-2005, an extensive renovation was carried out and the ventilation system was also adapted to today s requirements for good indoor climate.

Ventilation before the renovation Södra Bancohuset was previously stack venti-lated, where air with the help of temperature differ-ences, rises out via vents or tiled stoves, the stack effect. Replacement air, (outdoor air), was drawn in through leakage between window frames and window casements. This could create draughts in winter and no ventilation at all in summer. In addition, there were many rooms that lacked exhaust air vents or tiled stoves. Rooms facing south were very hot in the summer. The majority of windows could be opened, which was utilized in the summer, but not everywhere in the building due to noise disturbance from traffic. The stack ventilation was insufficient since the existing flues were not tight due to the settlement damage that the building had suffered. They were also partially filled with soot and mortar. The wet areas were fitted with exhaust air fans. Unfortunately these fans drew air from flues in nearby rooms, whose exhaust air thus stopped functioning.

Conditions for renovation of the ventilation systemThe building was constructed using that period s construction techniques with thick stone and brick external walls and with a layout designed in accordance with that time s architectural ideal with rooms opening into each other – enfilade – and with generous room areas and ceiling heights. Therefore the air exchange rate does not have to be as high as in newly constructed buildings with smaller room volumes.

Conservation principles With the installation of the new ventilation system the greatest possible consideration was given to the building s protection orders and the require-ment not to touch the frame of the building. By restoring the original flues, the building can be ventilated without visible installations. Authori-zation was given to drill holes in the chimneys

The western inner courtyard provides the main stairway with outdoor air. Behind the air intake grille there is a supply air unit which purifies the air and pre-heats it during winter.


in order to install propeller fans for exhaust air. Installation of new ventilation grilles in exist-ing, previously sealed windows facing the inner courtyards (for intake air), and the disassembly of existing internal windows in the main stairway in order to access air flow up in the stairway, was also permitted. Certain rooms had clogged ex-haust air vents in the brick flues and these were restored. By placing the exhaust air fans in the chimneys in the attic, the need for walkways and ladders to the roof was minimized and through that, additions to the building s protected exteri-ors have been avoided. Fitting the facades facing the south and west with awnings was possible since the building had been previously fitted with such. During the 1800s, awnings were commonly used to help lower the indoor temperature during the summer. Therefore, the installation of a cool-ing unit for the entire building was not necessary.

Ventilation after the renovationAll floors and half of the fitted attic floor have a ventilation system with controlled supply air. During summer, the exhaust air is mechanically controlled and during the winter rises thermally via the stack effect. The part of the attic floor that faces south, and can be very hot during the summer, now has a separate mechanical supply and exhaust air system with cooling and heat recovery. The unit is located in a plant room in the upper attic.

Supply air Replacement air is no longer drawn in via the windows, and due to this there are no unpleasant draughts, polluted air or disturbance from traffic. Naturally, the windows can be opened if you want extra ventilation during the summer. In the basement, which is on the same level as the inner courtyards, two supply air units have been installed. These units are located next to the building s two stairways. The units, which contain

Through the new-produced ventilation grille the supply air unit distributes fresh air into the main stairway.

Via the stairways fresh air rises and provides all floors with air.


filters, heating batteries and fans with silencers, get their air from the courtyards and blow it into the stairway. The air from the courtyards is less polluted than that on the street side. Since the building has a somewhat open design without closed doors, every room can be given the neces-sary volume of air via stairways and corridors. Those rooms that often must have closed doors have been provided with transfer air slots in the door frames, or silenced transfer air devices. The flow of the supply air fans is controlled by a pres-sure sensor on the 4th floor to ensure negative pressure in the building.

Exhaust airAfter the survey of the building s 17 clay brick chimneys (with a total of 66 flues) it was noticed that there were flues enough to equip every room with vents for exhaust air. In some rooms new holes were made in previously unutilized flues. All flues were then cleaned and sealed. The origi-nal exhaust air grilles have been retained. They are cleaned and re-painted. The existing plastic grilles were replaced with new grilles similar to the originals. Some grilles come from a previous renovation of the Manilla school. Since the exist-ing exhaust air flues have regained their original function, the ventilation in the winter can function with the stack effect. To ensure the flow of air in the summer, every chimney has been fitted with a rotational frequency controlled fan (pro peller fan), in the attic. The fans shall only be in opera-tion during the warmer parts of the year when stack ventilation ceases and will be regulated so that the right flow is obtained. The fans are not in use in winter. They provide virtually no resistance when turned off and therefore do not counteract the stack effect. Since the fans in the chimneys are jointly used for all flues in each chimney, all exhaust air vents in the rooms have been fitted with (hidden) control valves to adjust the air flow. Wet areas are connected to exhaust air fans which

The tiled stove in the Session hall has been fitted with an ex-haust air grille on the top. A carbon dioxide indicator speeds up the exhaust air automatically when needed.

Behind the exhaust air grilles, control valves have been mounted to adjust the flow of exhaust air. This ventilation grille has been recycled. It was saved from a previous alteration at the Manilla school in Stockholm.


are in operation year-round during the daytime. The assembly hall (the Session Hall) is fitted with an exhaust air fan whose flow is controlled by the carbon dioxide content. The carbon dioxide content is also measured centrally on a continu-ous basis from the 5th floor.

Experiences The property s tenants are satisfied with the new ventilation system. The air is perceived as pleas-ant. The sunlight-and weather-controlled awnings and the extra night cooling, when needed, give a good indoor climate even in the summer. The tenants have no problem with adapting to the building s conditions. It is important that no more workplaces are set up than the room s ventilation is dimensioned for. Those who work here must be aware that if the door to a room is shut, the ventilation decreases. When using the assembly hall and meeting rooms, meetings should be held with intermittent breaks for opening doors and windows. When stairways and corridors are used for supply air, as they are in this building, it is very important to have efficient and thorough cleaning so dust and dirt is not spread around. After the building s new ventilation system had been in use for a year, it was discovered that decayed mortar had sometimes loosened and fallen on the axial fans and caused interruption of service. Experi-ence has shown that the flues above the fans must also be sealed.

Outline diagram, flows in Södra Banco

Air inlet from the courtyards

Pressure con-trolled supply air units

Exhaust air via existing brick flues

Exhaust air fans in operation during the summer

Thanks to sunlight-and weather-controlled awnings, no cooling unit is needed. Södra Banco, Stockholm.

Supply air distributed via stair-ways and corridors


HistoryBetween 1904-07 financier, Ernest Thiel, con-structed a palace for himself and his family on Eol’s kulle (Eol’s Hill), Blockhusudden’s highest point on Djurgården. The architect was Ferdinand Boberg. Thiel was a major collector of contempo-rary art and his palace became one of Stockholm’s most beautiful Art Nouveau buildings.

RenovationThe building underwent a major renovation in the early 1930s in order to better adapt to the museum operation. A new apartment for a curator was furnished in the western part of the building. In the mid-1960s, the facades were re-plastered with grey and defective plaster. In the 1970s the walls in the exhibition halls were covered with fibreglass weave, painted with semi-gloss plastic paint, and fluorescent lighting was installed in the ceilings. The building underwent a restoration in different phases between 1999-2004. Then facades once again got a smooth and white plas-ter and the exhibition hall walls were filled and painted in a light grey tint to resemble the wool fabric that originally covered the walls. In connec-tion with the facade renovation, a re-utilized old-style ventilation grille was mounted on the entry facade to cool the Munch Exhibition Hall.

Ventilation before the renovationThe building was originally constructed with a calorifère system for ventilation. The exhibition

Owners

The palace was owned by Ernest Thiel until

1924 when the Swedish state purchased the

building, including his entire art collection.

Today, the building is owned by the National

Property Board Sweden.

Tenants

The palace was a private residence until

1924. Thielska Galleriet opened to the public

in 1926 and is still currently a museum

with the most complete collection of the last

century’s Nordic artists and includes works

by Edvard Munch, Anders Zorn, Bruno

Liljefors, August Strindberg and others.

8. Thielska galleriet

Thielska galleriet is located on Eol’s kulle on southern Djurgården.

Djurgården, Stockholm




historic building since 1993 and is subject to pro-

tection orders, which state that alterations to the

building’s structure may not be carried out without

the authorization of the Swedish National Heritage

Board.

The exhibition halls in Thielska galleriet are ventilated by the building’s calorifère system.

A close-up view of the roof to the Munch Hall with exhaust air hoods, and further away, the cupola. The small photo shows the cupola’s exhaust air opening.

halls were ventilated with air that is pre-heated in a heat chamber in the cellar and distributed via sheet metal and brick ducts. The domestic part of the building uses stack ventilation. Over time, the ducts had become clogged with leaves and dust. The ventilation functioned poorly. The Munch Hall, which is provided with daylight through a lantern, was very hot in the summer because the lantern was poorly ventilated.

Conditions for renovation of the ventilation systemThe building is unique and the art requires a cer-tain indoor climate in order not to be damaged. Installing a modern and visible ventilation system was not possible. The ambition has been to repair the old system and complement it with installa-tions that do not impact the architecture of the building.

Conservation principlesIn 1993 the building was protected by a pres-ervation order stating that neither internal nor external alterations to the building's original ap-pearance may be carried out without the authori-zation of the Swedish National Heritage Board. The renovation between 1999 and 2004 involved restoring the building's internal and external finishes. Authorization was granted to mount a re-used old-style intake air grille on one of the facades.


Ventilation after renovationThe building’s calorifère system was retained and given better functionality by cleaning the intake air ducts. In this way the original function of the venti-lation was restored. Despite this, the Munch Hall, with its lantern, was too hot in the summer. To solve this problem, a duct fan was installed in an unused brick duct, which was further connected to a new sheet metal duct, debouching in the lantern. A new intake air grille was mounted in the brick duct at the ground floor in the museum’s entry facade, which faces north. In this way, cool air is pressed into the lantern, which is then ventilated through the stack effect via roof hoods.

Intake airThe building has two different systems for bringing outdoor air into the rooms. The large exhibition halls gets the air, which in winter is pre-heated, via the heat chamber that is part of the building’s calo-rifère system. Through brick ducts the air rises into the exhibition halls via grilles mounted high on the walls. In the domestic part of the building, the outdoor air is drawn in through vents and gaps between the window casements and frames.

In the heat chamber, the air is heated by radiators that are mounted in the ceiling.

Here, air is taken into the calorifère chamber. The damper can be positioned manually for the desired air flow.

The Munch Hall’s lantern is now cooled with outdoor air that is drawn in through this newly installed grille, which is re-cycled from a previous renovation at the Manilla school.


Outline diagram, flows in Thielska galleriet

Exhaust air via brick flues

New duct fan for the cooling of the Munch Hall’s lantern

Air intake via a heat chamber; so-called calorifère

The lantern above the Munch Hall is cooled by cool air in the summer.

Exhaust air grille in the cupola room. In 1978, Karl Axel Pehrson added this decoration to the cupola.

Heated air from the heat chamber is distributed upwards in the building through brick ducts.

Exhaust airAll rooms have exhaust air through stack ventila-tion via brick flues. The lanterns above the large halls are also ventilated by the stack effect, using hoods.

ExperiencesThe calorifère system functions poorly in the sum-mer. Initially, installation of a fan in the heat cham-ber was planned but never carried out. If this was done now, it would possibly provide more effec-tive cooling for the exhibition halls. Cooling of the Munch Hall has been improved through the measures that were taken.

Lantern


Axial fan = propeller fanBackground ventilation = the lowest air exchange

(ventilation rate) in a roomCeiling fan (Casablanca fan) = fan mounted in

the ceiling used to even out temperature differ-ences in the room

Climate cooling = cooling unit that cools the room to a comfortable temperature

Conservation plan = describes conservation requirements of the property and long-term goal for the preservation and management of the building

Control valve = an exhaust air terminal device for adjusting the air flow. It can be mounted in an exhaust air vent, to obtain the adequate volume of exhaust air from a room into the flue or duct

Cooling baffle = a chilled beam, containing a cool-ing battery, using water to remove heat from a room

Cowl = a sort of chimney cap that turns round with the wind so as to present its opening to the leeward and therefore creates negative pres-sure in the flues. It increases the stack effect

Damper = device for adjusting the air flowDraught = unpleasant air movementDuctwork = composite system of ventilation

ductsEmissions = gases that are emitted by paint,

furniture, etcExhaust air = used air that is conveyed outside

mechanically or via the stack effect Exhaust air device = is used to carry air from a

roomExhaust air system = system where the exhaust

air flow is controlled by a fanFan air-heater/cooler = battery in the ventilation

system used to heat or cool air

Fan-assisted stack ventilation = during the varm part of the year, when the stack effect ceases, the exhaust air is governed mechanically.

Fan coil (fan convector) = device equipped with fan and heating and/or cooling battery intended to climate-adapt a room

Fan ventilation (mechanical ventilation) = ventila-tion with the help of fans

Heat exchanger = device used to transfer heat between exhaust and intake air

Heating plant room = space for technical equip-ment for heating

Heat pump = heating device that utilizes the free energy that exists in, for example, exhaust air, outdoor air, water or the ground

HVAC = heating, ventilation, air-conditioningIncreased air flow = largest air flow (ventilation

rate) in a room (in the event of increased heat or a large number of people)

Intake air = external air that is conveyed into a room or into a supply air unit

Intake- air radiator = specially designed radiator with an air-inlet that pre-heats outdoor air

Installation system = heating, cooling or ventila-tion system

LCC (Life Cycle Cost) = the concept includes both the investment and operation costs during a system’s lifetime

Night cooling = cooling of rooms at night with the help of cooler outdoor air via mechanical or natural ventilation

Operating time = time when the system is in operation

Outdoor air = external air, outside airOVK = obligatory ventilation inspection according

to Swedish legislation

Glossary


Radial fan = Fan with wheels that rotate in a shell-formed capsule and draws in air axially and throws it out radially; also called a centrifugal fan

Replacement air = make-up air, the required vol-ume of air supplied into a room, compensating for the same volume of exhausted air, extracted mechanically or via the stack effect

Reversible installation = installation that can be removed without leaving major marks in the building frame

Ridges = upper part of the attic above the truss ties

Rotating heat exchanger = heat exchanger con-sisting of a rotor, equipped with air ducts, which passes alternatively through the exhaust and intake air flows to transfer heat

Slotted vent = an intake air device for providing outdoor air into a room

Stack effect = is the movement of air. When there is a temperature difference between two ad-joining volumes of air, the warmer air will have lower density and be more buoyant thus rising above the cold air creating an upward air stream driven by buoyancy

Stack ventilation = natural ventilation that func-tions without the help of fans due to the temper-ature difference between two adjoining volumes of air. Warmer air has lower density and is thus more buoyant and rises above colder air, creating an upward air stream

Supervisory authority = authority whose task it is to ensure that laws and provisions that fall within the authority’s area of operations are adhered to

Supply air device = is used to provide air to a room

Supply and exhaust air system = system where both the exhaust and supply air flows are controlled by fans, often called a balanced ventilation system

Timer = device used for timingTransfer air device = device, mounted in a wall be-

tween two rooms to distribute airTransferred air = air that is carried from one room

to anotherTransom = horizontal frame/beam that separates

the upper ventilation casement from the lower casement in a window

Trickle ventilator = an intake air device, fitted to a window casement or frame, for providing out-door air into a room

VAV-system = supplies variable volume of con-ditioned air for heating, ventilating, and/or air-conditioning

Ventilation = movement of air into or out of a space, to provide fresh air, to carry away moisture, odours or dangerous gases or to allow free flow in drains

Ventilation flow = air volume per unit of time; often measured in litre per second, l/s

Vent convector = wall-mounted device equipped with a heat battery for providing pre-heated outdoor air

National Property Board Sweden +46 8 696 70 00 www.sfv.se

Tradition is change. Sweden has many buildings and environments of great value to its

national cultural history. Each one is part of the nation’s history and its future.

The National Property Board aims to make all Swedes proud of these national treasures –

palaces and royal parks, theatres, museums, embassies, and property comprising one seventh

of the total land mass of Sweden. All are owned by the Swedes collectively, and the duty of the

Board is to administer them in the best possible way.

Our task is not only to maintain the soul and character of each building, but also to adapt

them to present day needs and uses for the benefit and enjoyment of tenants and the general

public alike. Just as important as passing on the history behind existing buildings is the creation

of new buildings worthy of the future. We are therefore commissioned by the Swedish govern-

ment to carry out new building projects which in various ways are representative of our nation.

We also administer state-owned forests and land in a sustainable manner so as to preserve

bio diversity and maintain reindeer pasture lands for the benefit of future generations.

Desig

n: Dick N

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ventilation in historic buildings b-2

Documents

history of ventilation

ventilation principles

chapter ventilation

accepta ble ventilation

ventilation system

old ventilation system

historic buildings contents

historic buildingsthe