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Summary of Items Discussed in 2/2016 APSEC Discussion Forum on 18 March 2016

Items proposed by Convenors for Discussion Summary of Discussion and BD’s Responses

Items raised by HKIA 1. Location of Residential Recreational facilities

In recent discussion with BD officers, it is commented that Residential Recreational facilities (RRF) is no longer acceptable to be located within residential towers. Please clarify whether the Recreational Facilities in the following diagrams are acceptable: a. RRF occupying the whole top floor of residential towers, with or without

exclusive access. (Case A)

Provided that the RRF proposal met the requirements and conditions stated in PNAP APP-104 and the RRF was for the exclusive use of the owners and residents and their bona fide visitors only, the three locations of RRF were all acceptable. In this regard, RRF should be accessed through common areas of the development without attracting direct access from streets thus the use by non-residents. Whether to provide lifts for the exclusive use of RRF should not be a concern under the above conditions.

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b. RRF occupying part of the top floor of residential towers, with or without exclusive access. (Case B)

c. RRF occupying the lowest floor of residential towers with exclusive

access (Case C)

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2. Enclosure Wall Separating Protected Lobby with Covered Landscape Area As per item 9(e) of the APSEC Discussion Forum dated 18 May 2012, we were advised that the design of the ground storey discharge point recessed from the ultimate edge of the building might be acceptable if the covered recessed area was a common area, open in design and not encumbered with features carrying fire hazards, i.e. the exit route at such covered recessed area need not be enclosed by fire barriers. Following the same principle, if a protected area (say, a Fireman's lift lobby) is recessed from the edge of the building and the covered area (say, covered landscape area) surrounding such protected lobby is a common area, open in design and not encumbered with features carrying fire hazards, the

The considerations would be similar to those in accepting a fireman’s lift lobby recessed from the edge of buildings without fire barriers . Provided that the recessed areas were common parts, open in design (not trapping smoke) as well as not encumbered with fire hazards (such as loading/unloading bay), the design would be favourably considered. The non-FRR external enclosure to such protected area/lobby should not be within 6m of unprotected openings pursuant to Clause C9.7 of the FS Code, and the covered areas surrounding the protected area/lobby, if any, should be designed with reasonably high headroom to facilitate the dispersal of smoke in case of fire.

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external enclosure wall separating such protected lobby with the covered landscape area will NOT need to be of fire-resistant construction, provided always that any non-emergency services within such protected lobby be enclosed by fire barriers. Please advise if our understanding is correct.

3. Effective Dates for Versions of FS Code There are 3 versions of the FS Code, September 2011, April 2012 and October 2015. It seems that the effective dates of each version and how they will affect on-going projects are not stated. Would BD please clarify the effective dates in relation to project status, such as foundation or building consent previously granted?

For assurance of building safety, revisions should be in force upon promulgation unless otherwise specified. However, for situations where foundation consent had been granted before the revisions, BD would review the difficulties encountered in following the new requirements on case basis and take a pragmatic approach if necessary.

4. PNAP APP-152 A new version of PNAP APP-152 was issued in Jan 2016, but no effective date was mentioned. Would BD please clarify the effective date and how it will affect on-going projects?

As the revisions in the new version of PNAP APP-152 were predominantly relaxations of requirements, they were intended to be of immediate effect for all projects irrespective of status. However, as mentioned in item 3 above, if there were difficulties in meeting the tightened measure on vertical greenery, BD would review the encountered difficulties on case basis and take a pragmatic approach.

5. PNAP APP-2 (Mar 2015) In PNAP APP-2 (Mar 2015), Appendix B (Section of Curtain Wall System Installed at New Building) is omitted. Would BD please clarify the reason behind the omission?

The Appendix should be included in the PNAP and would be posted to the website asap.

6. Proof of Ownership of Land According to para. no. 3 of BD circular dated 29/7/2013 (which is referenced

The BA had the legal power to require proof of ownership of the land

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to BD circular dated 20/10/2010), the applicant is required to submit the ownership proof if the proposed works will involve erection of a new building. However, the BA is prepared to exempt the requirement for submission of ownership proof, if such building is not GFA and SC accountable. In some development site with multiple ownerships (e.g. school (non-domestic) and commercial (non-domestic)), GFA would be allocated to different private premises under one lease. Would BD please clarify in what scenario ownership proof with confirmation of no objection from all individual owners is required for A&A works?

forming the site for the purpose of development control under B(P)R. Assessment of GFA (PR) or SC inevitably involved establishment of site thus requiring proof of ownership. [Post Meeting Note: The Court of Final Appeal stated on 19 May 2016 that “it is no exaggeration to say that the site is the single most important determining factor in a plan.” The BA is legally entitled to require ownership proofs of site.] As stated in the streamlined administrative procedures published in the relevant circular letters, proof of ownership was required when new buildings were involved but BD might, on case merits as a streamlined measure, not require such proof when the proposals involving new buildings incurred only revision of GFA and SC that balance off within the subject premises without requiring assessment of PR and SC of the overall site. However, BD making the discretion not requiring such proof in these circumstances was mainly for streamlining of procedures and did not automatically imply that the owner had the legal title over the involved GFA or SC. Members’ attention is drawn to s.14(2) of the BO.

7. Open Kitchen Smoke Detector Location Under Clause 13.4(e) of the FS Code, for open kitchen in premises with internal staircase(s), a barrier of not less than 450mm measured vertically downwards from the underside of the floor shall be provided. The barrier should surround the notional open kitchen area and should have an FRR of not less than -/30/- and be non-combustible complying with the requirements

The effect of the smoke barrier should have been thoroughly considered during the review of the FS Code by the Technical Committee. Notwithstanding the above, BD explained that one of the consideration of not putting the smoke detectors in the notional kitchen areas was to avoid false alarms. On the other hand, the

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in Part E. If false ceilings are hung in the open kitchen, the barrier should extend not less than 450mm below the false ceilings. For units with an open kitchen, the sprinkler is usually installed within the “notional kitchen area” while the smoke detector is usually installed at the living area. If 450mm smoke barrier is installed to surround the notional kitchen area, smoke would be trapped at the kitchen and would delay the action of the smoke detector. Would BD please advise if this arrangement is acceptable (to both BD and FSD)?

450mm vertical barrier would help trap smoke thus speed up the activation of the sprinkler in the notional kitchen area. After the smoke reservoir formed by the barrier was filled, overspill of smoke from the notional kitchen area would also trigger the smoke alarms. The requirement of 600mm vertical barriers (screen walls) next to exit doors was also discussed. BD advised that the 600mm barriers were required for protecting the evacuees from radiant heat generated from the stove when they pause to open the escape doors. It should be an independent consideration of whether there was a nominal passage between the stove and the exit door. The concern should be the need to screen evacuees from radiant heat generated by stove fire.

8. High Rise Green Wall As it can improve our urban cityscape, provide natural green shading, offset carbon dioxide, and improve micro-climate of the city, high rise greenery is beneficial to the community at large. Current vertical green wall can be exempted from GFA calculations for a maximum of 300mm, and it relies on maintenance from the external side using a cherry picker or gondola. For high rise vertical green wall, it is proposed to allow a greater depth of, say, 1m for high rise green wall, in order to provide a maintenance access from the internal side as an alternative to the use of a gondola. Samples of catwalk for high rise greenery is shown below. For comparison, another photograph below shows a vertical green wall maintained by gondola in Hong Kong.

On case basis, BD was prepared to consider GFA exemption of open catwalk system for maintaining high rise vertical greenery wall. Favorable considerations had already been given to innovative, non-bulky and perforated designs not obstructing air movement and not prone to misuse.

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9. Active Double Layer Green Wall

Active double layer green wall system as shown below is a popular green feature adopted worldwide. It is suggested allowing GFA exemption for active double layer green wall system within the limit of the 10% cap.

Ditto

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10. Skygarden

Skygarden can improve microclimate, reduce heat island effect and provide amenity spaces for inhabitants. It is proposed to allow exemption from GFA calculations for skygarden in non-domestic building.

Communal sky gardens for non-residential buildings had been permitted under JPN2 (Appendix A1(d)) to be exempted from PR calculations subject to conditions such as no commercial activities therein. BD advised that they would review the exemption criteria for sky gardens in non-domestic buildings together with those in domestic buildings with a view to making the criteria on par with each other.

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11. Innovative Building Forms Below are some overseas examples of innovative building forms for discussion on GFA and site coverage interpretation in Hong Kong. (Source: Internet) Example 1

Innovative and creative designs other than the current setback and open space approaches as stipulated in PNAP APP-132 to achieve a better environment or streetscape were always welcome. [Post-meeting note: Further research on the window requirements for habitable spaces in Singapore had revealed that Singapore had much less stringent requirements on prescribed windows compared to the Hong Kong Building Regulations. HKIA would share their findings in the next forum.]

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Example 2

Example 3

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12. Follow up on Flue Aperture Having read the post forum advice from EMSD on item (4) in the 5/2015 APSEC Discussion Forum held on 13 Nov 2015, it appears that electric water heater would be the only solution for residential units with open kitchen and internal bathroom as use of superslim type gas water in habitable space, i.e. living and bed room, is not preferable and yet use of box type gas water heater is not advisable. If it is the case, the BD is requested to consider waiving the requirement of flue aperture in such units.

While the difficulty in the provision of flue apertures in the situation as described was appreciated, BD would further liaise with EMSD to review the possibility of omitting the flue openings in certain congested building designs and would be pragmatic in accepting alternative provisions. [Post Meeting Notes: EMSD had strong reservation on exempting such provision in a new building even without gas supply unless effective measures could be strictly implemented in prohibiting occupants from shifting to gas water heaters in future. EMSD concerned that even there was no supply of piped gas, it would still be feasible and very convenient to use LPG cylinder as alternative fuel source. BD was

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following up with EMSD on the possible means of posing such restrictions in return for not providing the flue openings.]

13. Two A.P. in One Site Sometimes, such as in sites owned by MTRCL, URA or Airport Authority, GBP may be submitted to BD by one A.P. for approval prior to auction of the sites. After the site is sold to a developer, probably another A.P. will be taking over the site. The question is if the GBP submitted by the first A.P. is still in the approval process, can the first A.P. remain as the A.P. solely for the approval of the plan until the approval of the plan while the second A.P. can submit Form BA4 at the same time for other site activities?

To facilitate the operation of the building industry, the BA had made the discretion of accepting GBPs submitted from two APs for the same site on case basis subject to clear indication to BD on the respective responsibilities of the APs. The scenario as mentioned could be acceptable subject to works not yet commenced on site. For sites under construction, very clear and discrete demarcation of the site (usually different parts of the site without being complicated by different storeys of a building) under the independent supervision of the two APs must be identified for the BD’s consideration.

14. Liability of A.P. Submitting Plan only Sometimes, after an A.P. obtains GBP approval for a site, the site may be sold to another developer who will appoint another A.P. to take up the job. Should the first A.P. resign before the new A.P. submits a brand new set of GBP without using the approved GBP (especially when two years have elapsed)? Furthermore, after obtaining GBP approval for a site, if the site kept idle without any further development, would the A.P. be liable for activities happening in the site without his knowledge?

For sites where building works had not been commenced yet: Unless otherwise stated and found acceptable by BD, once the owner appointed a new AP by the submission of a new Form BA4 superseding the previous one, he had in effect informed BD that the first AP was no longer appointed. If a new Form BA4 was submitted without superseding the previous one, reasons for the appointment of 2 APs at the same time must be clearly stated for consideration by BD. The principle in item 13 above should then apply. The succeeding AP need not wait for the former AP’s notification to BD on cessation of service in order to be appointed. In principle, the owner should be responsible for the safety of the

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existing building or site when the proposed building works under the supervision of the AP had not been commenced. BD emphasized that consideration might differ from case to case. For sites with building works commenced: The outgoing AP must notify BD his cessation of service, the consequential site arrangement and his certification together with relevant parties (RSE, RGE, RC as appropriate) that the extent of works completed under his supervision were satisfactory. [Post meeting note: BD reminded that the copyright issue should also be cleared amongst the relevant parties.]

15. Drainage in Sunken Slab In PNAP APP-93, it is stated that “where the backfilling of void space is unavoidable, sufficient access points……… should be provided to facilitate inspection of every part of such pipeworks and clearance of any blockage thereof.” While the PNAP stipulated that sunken slab should not be backfilled unless certain conditions are fulfilled, such practice is common for Hong Kong residential buildings for ease of construction and meeting the expectation of future owners. BD is requested to advise whether such practice is still acceptable provided that all the relevant BD’s conditions are complied with.

BD advised that a PNAP would be issued in due course on restriction of using concrete to backfill voids for running drains in the sunken slab situation. To facilitate the future maintenance of the embedded pipes, light weight concrete or sand should be used instead, if backfilling was necessary.

16. Laundry in House or Large-sized Flats It is understood that laundry in a residential premises is considered as ‘habitable space’. Putting aside the provision of laundry in a normal sized flat, it is believed that provision of laundry is reasonable in a single family

BD suggested considering the provision of larger utility rooms for housing the laundry/drying machines together with other utility equipment and facilitating the provision of windows.

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house or a large sized flat, say over 500 sm. In such case, the necessity to provide prescribed window to a laundry would be superfluous. BD is requested to consider waiving such requirement of prescribed window for laundry in single family house and flats over certain size subject to provision of mechanical ventilation similar to that of an internal bathroom.

Item by HKIE 17. Maintenance Catwalks and Cat Ladders

Please clarify whether approval and consent is required for maintenance catwalks and cat ladders in the ceiling of plant-rooms, bus terminus, car parks, auditorium, sports halls etc. & for maintenance catwalks sitting on low plinths (not more than 600mm tall) on roof. Some reference catwalk details are enclosed for your easy reference. Example 1

BD advised that in general, approval and consent were required for structural works of all steel platforms, catwalks shown on GBPs. However, cat ladders in inaccessible areas for public could be shown in GBP only.

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Example 2

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Example 3

18. Cold-Formed Pile Pipe for ELS works Please clarify whether cold-formed pile pipe with a thickness below 22 mm can be adopted for ELS works.

All cold-formed steel designs in accordance with the prevailing Code of Practice for Structural Use of Steel were acceptable to the Building Authority.

Item raised by HKIS 19. Clause B30.4 of FS Code

For compliance of Clause B30.4 of Fire Safety Code, please clarify the number of direct intercom link for temporary refuge space (TRS) if two separate TRS are provided at typical lift lobby with the following positions: a) At opposite walls. b) Adjacent and at the same wall.

For scenario (a) - TRSs at opposite walls, one direct intercom for each TRS should generally be provided unless for short distances. For scenario (b) – adjacent TRSs at the same wall, one direct intercom at a location reachable from both TRSs should suffice.

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20. Clause B8.2 of FS Code For industrial wholesale conversion project (multi ownership case), in order to comply Clause B8.2 of Fire Safety Code (i.e. gain access to other required staircase at anytime), is it acceptable for designating a right of way within the private premises with demarcation on GBP?

Designating a right of way within the private indoor premises as a MOE would not be practical and not acceptable under BO.

21. Office on Basement Floors For a building with approved use of basement as shop, if it is to be converted into office use, can the B(P)R 30 be waived with similar criteria under PNAP ADM 2 being met? Also, for new development with basement for office, can the B(P)R 30 be waived with similar criteria under PNAP ADM 2 being met? Our member have seen precedent cases but currently not listed in the PNAP.

Office on basement floors was not acceptable unless it was an ancillary office to other primary uses.

22. Measuring the width of the required staircase For measuring of the clear width of the required staircase, please clarify if the

Referring to the diagram, BD confirmed that the width of the required

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width shall be measured between the wall finish and the inner side of the balustrade excluding the bottom solid concrete curb which comply with APP-110 of 150mm H. and protruding width less than 75mm.

staircase should be measured between the inner side of the balustrade and the wall finish provided that the solid curb with the width at its top on the inner side of the balustrade was not more than 75mm.

23. F&B Licensing Application Upon OP/BA 14 submission, when there is F&B licensing application for the premises marked as "Retail/Shop" in the approved GBP in the same time, please clarify whether the GBP need to incorporate those works in licensing plan before works completion. For A&A submission, please clarify whether the DV of the building need to be updated according to the information of existing F&B premises (original marked as "retail" in last approval) outside the A&A submission area.

BD replied that for OP/BA14 submissions, there would be no need to include those non-building works for the purpose of license application. For A&A submission, it was necessary to update the overall DV of the building with individual existing licensed premises for BD’s reference. The appointed AP could write to the Licensing Unit of BD to obtain the residual DV figures at the date of enquiry for incorporation in the GBP.

24. Fire Damper Please clarify whether it is required to mark all locations of fire damper and FRR enclosure to E&M service in the GBP.

The extent of indication would depend on situations. Generally, for new GBPs of large developments, it would not be necessary to mark

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locations of fire dampers and FRR enclosure of E&M services. AP should indicate in the general notes of GBP for such provisions e.g. at the ends of ventilation ducts. However, the AP might choose to mark such in simple A&A plans for small scale works.

Item raised by AAP 25. Flue Aperture at Balconies

The apertures (notional or actual) may be placed so as to vent into permanently open and well ventilated balcony approach …… (APP-27 item 5(a)). Is such ‘ventilation arrangement’ not-be regarded as ‘bathroom exhaust outlet’ jeopardizing the exemption criteria of balconies under JPN1, Appendix A – item 1(a)(ix).

Bathroom exhaust outlet was intended to be a separate provision from discharge of gas exhaust through flue aperture. For a flue aperture provided at a balcony, it should be located at positions where there was no obstruction to restrict the vertical flow of air.

26. Structural Columns/ Walls Accountable for GFA Calculation Members have encountered cases where BSs requested AP to demonstrate that less than 50% of the floor area of a floor is GFA accountable, or otherwise the structural columns/walls within the GFA non-accountable areas (such as E/M plant rooms) needed to be counted in GFA calculation. As far as we know, there is no such 50% requirement in the regulations or practice notes. Please clarify if there is such guideline.

BD confirmed that structural columns/walls within the GFA exempted areas that occupied less than 50% of the area of the floor should be accountable for GFA. Structural columns/walls within the GFA exempted areas that occupied more than 50% of the area of the floor should NOT be accountable for GFA.

27. Updated Site Area and Site Boundaries (PNAP ADV-33) In accordance with PNAP ADV-33, a survey plan prepared by an authorized land surveyor (ALS) to update the site area and site boundaries shall be submitted as essential information for GBP submission. However, the updated site area may be different from the site area under lease or BD’s record of the development site. Would BD please clarify on the ways to determine site area

BD advised that: Scenario 1 – (Land Survey Plan (LSP) areas larger than lease area If there was no obvious error noted in the LSP e.g. inclusion of adjoining unbuilt upon site area into the subject site, the AP should proceed to liaise with DLO to carry out lease rectification or

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in the following scenarios: Scenario 1 If site area based on updated survey is larger than the site area under lease, which site area shall be used under BO? And what is DLO's view on the site area discrepancies? Scenario 2 If site area based on updated survey is less than the site area under lease, which site area shall be used under BO? And what is DLO's view on the site area discrepancies? Scenario 3 If updated site boundary survey indicated adjacent development encroached into the development site, will it affect the site area and/or development potential of the development site?

modification. BD might in parallel accept the LSP’s surveyed area in the GBP approval process subject to clarification and would draw the AP’s attention to BO s.14(2). Despite the above, the AP should proceed with the construction conservatively based only on the smaller site area until the discrepancy was clarified and ownership of the “additional” site areas was confirmed. Scenario 2 – LSP area less than lease area Smaller site area shall be adopted because it was the site area physically measured. Scenario 3 – The part of structure that encroached into the site would be accountable for GFA and SC. Subject to ALS’s confirmation and there was no adverse possession positively ruled by court, the surveyed site area shown on LSP would be acceptable. Members advised that BD’s stance appeared to be conflicting in Scenario 1 and 2. The matter would be further discussed in coming task force meeting.

Items raised by BD 28. Structural Design of Aluminium

At present, the structural design of aluminium elements of curtain/window walls is based on BS 8118-1:1991, which is an ultimate limit state design

While there was no objection received during the meeting to the change of partial load factor for wind load for the structural design of

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approach with a partial load factor for wind load of 1.2 as specified in Table 3.1. BS 8118-1:1991 has been replaced by various parts of BS EN 1999 which also adopts an ultimate limit state design approach. In view of general practice being adopted by the building industry, the use of BS 8118- 1:1991 for the design of structural aluminium works will continue to be accepted for local applications. However, to tie-in with the partial load factor of 1.4 for wind load adopted by the CoP for Structural Use of Concrete 2013 and CoP for the Structural Use of Steel 2011 for concrete and steel structures respectively, the partial load factor for wind load for the structural design of aluminium elements of curtain/window walls, for which the wind load is usually the most dominant applied load, will be changed from 1.2 to 1.4.Accordingly, the PNAP APP-53 will be amended in the near future. It is stated in clause 3.2.3 of BS 8118-1:1991 that the partial load factors in Table 3.1 are for guidance but different values may be used by agreement between the designer and the client. As such, the proposed change of partial load factor for wind load does not violate the provisions of BS 8118-1.

aluminium elements of curtain/window walls from 1.2 to 1.4 when PNAP APP-53 would be revised in near future, BD was seeking views from the convenors on the grace period for the application of the new requirement. It was generally agreed that the new requirement would not apply to the projects with the foundation consent granted in the case of new developments. For A&A projects, reference would be made to the current practice when determining the effective date of the new requirement.

AOB items 29. BFA Access Route Requirement for projects with one Single Family

House (Item raised by AAP) According to Design Manual : Barrier Free Access (DM:BFA) 2.1.2, the application of Table 1 and Table 2 is not necessary for Exemptions listed in DM:BFA 2.2. According to DM:BFA 2.2, under 2.2.1(a), "Buildings of 13 m or less in height above ground level which are used, or intended to be used, for occupation by a single family..." is one of the Exemptions and the

BD stated that it would require more time to deliberate the subject. [Post meeting note: BD confirmed that BFA access to individual houses would not be required but that to the communal facilities should still be provided.]

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Obligatory Design Requirement need not apply. It is our understanding that ALL Obligatory Design Requirements, including 'Access Route' need not be complied for projects with one or more than one single family houses. We would like to confirm if our interpretation is correct.

30. Sub-Working Group of Quality of Drainage Plan Submissions (Item raised by BD) BD was finalizing the checklist for drainage plan submission and the comments on the sample drawings prepared by HKIA/AAP. The refined sample drawings incorporated with BD’s comments and checklist would be circulated to members for comments once completed. Subject to no major comments received, the checklist and sample drawings incorporating the members’ comments would be incorporated into the revised PNAP ADV-33.

It was agreed that if no major comments were received, the refined checklist and sample drawings would be confirmed by circulation. [Post meeting note: the materials were circulated to sub-working group members on 6 April 2016.]

31. Working Group on Site Areas under Joint BSC & APSEC (Item raised by BD) BD informed that the following items would be discussed in the coming meeting: Number of decimal places which rounding should be performed for the

measurement and computation of site area; and Cases studies and formulation of guidelines in handling discrepancy of

site area information from different sources. Furthermore, BD had researched on the BO and confirmed that BD had been

Guidelines would be formulated by the Working Group.

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empowered to request the submission of land survey plan and could refuse the application for consent if the land survey plan had not been submitted or found unsatisfactory.

32. Revision of the Requirements of Design Manual : Barrier Free Access (Item raised by BD) The Technical Committee (TC) on the DM:BFA had been collecting views and considering comments or feedback received from rehabilitation sector and practitioners on the use of the Design Manual and would propose corrigenda to the DM:BFA(2008) which would include the following items: a) Vertical lifting platform It is proposed to formulate the general criteria for accepting the use of the vertical lifting platform in new or existing buildings in lieu of accessible passenger lift or ramp due to planning difficulties; b) Braille and tactile fire exit map More information including door of individual room is proposed to be incorporated into the braille and tactile fire exit map. c) Visual Alarm System It is proposed that provision of visual alarm should be mandatorily required at all types of buildings except for exit staircases & their smoke lobbies and domestic units. Although the corrigenda of the Design Manual would be circulated to

It was agreed that the convenors would further deliberate on the issues within their institutes/ association and liaise with their respective representatives in TC to present their stance.

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institutes and associations for consultation in the form of BSC and APSEC papers, BD would like to brief them in advance so as to facilitate collection of views within each institute/association. .