performance requirements for pbus in gls sites€¦ · performance requirements for pbus in gls...

Performance Requirements for PBUs in GLS Sites

Outline

Introduction on PBUs

Considerations for Good PBU Design

Good design requirement and framework

Productivity Gains, Time and Resource Management

Introduction on PBUs

• Productivity impact – 60% in manpower and time savings

• Environmental Impact – much less noise and dust, shorter construction period

Finished PBU Lifting PBU in place PBU in factory

St Regis Residences, Singapore, since 2006 Parc Emily, since 2005

More than 14,000 PBUs have been installed in private residential developments.

2000

2008 - 2009

2010 - 2011

2012 – 2013 Current

Private Residential Projects that adopted PBU

More than 14,000 PBUs installed in

20 projects

Trellis Tower

Concrete floor with

cement board walls

Concrete floor / Steel wall

Parc Emily, St Regis

Residences, City Square

Residences, Tribeca

Concrete floor/ concrete wall

The Sail @ Marina


The Oceanfront @ Sentosa

Cove, One Shenton, Livia,

Wilkie Studio, Shelford Suites


Cliveden @ Grange


NV Residences, Hundred

Trees, Tree House, The

Glyndebourne


The Arte @ Thomson,

Quayside W Residences @

Sentosa Cove, Cube 8, 368

Thomson


Haus @ Serangoon Garden,

Up @ Robertson Quay, Lush

Acres


Blossom Residences, H2 O

Residences, Echelon,

D’Nest, Jewel @ Buangkok

Cube 8

368 Thomson

Parc Emily

Examples of some other past private residential projects that have adopted PBUs:-

VIDEO CLIP: INTRODUCTION TO PBU

Wall & Floor: Concrete

Wall: Drywall panels

Floor: Concrete

Wall: Lightweight Concrete

Floor: Concrete

Wall : Ferrocement

Floor: Concrete

Wall: Steel Panel

Floor: Concrete

Wall & Floor: Fibre-reinforced panel

(FRP)

DIFFERENT TYPES OF PBU

Differences in PBU types

Materials & Structure

Delivery of PBUs to site

Method of installation

Method of maintenance

Weight & Ease of

Handling

Volumetric Concrete PBU

Floor/wall made of precast concrete

Can be fabricated by monolithic casting

or cast in few stages

Service pipes are either cast in or

installed in recesses provided on walls

Usually installed by critical as PBU is

too heavy to be pushed

Double-slab approach is preferred

MATERIALS AND STRUCTURE

Lightweight Concrete PBU

Floor/wall made of light weight concrete

Wall thickness is 50mm, maximum

weight including finishes is 3.5

tonnes for dimensions 2 m x 2 m

(Based on Bathsystem’s lightweight

concrete PBU)

Recess provided on walls to conceal

service pipes

Can be installed by critical & non-critical

method

Double-slab approach is preferred

Installation speed: 20 units/day with four

installers (Based on Bathsystem’s

experience)


Drywall PBU

Floor made of cement board/concrete

concrete and wall made of drywall

Steel sections for floor and wall frame

For cement board floor and drywall,

maximum weight of 2.0 tonnes including

finishes (Based on Bathsystem’s Super

Light PBU)

Water pipes are concealed in the dry wall

Backing plates on the wall to mount the

fittings and accessories

Non-critical path installation


Fibre Reinforced Plastic (FRP) PBU

Floor made of cement board/ FRP floor tray and

walls made of FRP

No waterproofing required

Panels are connected by bolts

Grids are sometimes found at bottom side of FRP

floor tray for strengthening purpose

FRP wall panels with laminated finishing are

available, thus eliminating need for tiles

Non-critical path installation

Alternative lightweight panels in market include

glass fibre-reinforced polymer (GFRP) and sheet

moulded compound (SMC) that are also used for

panelised system


Wall panels sit on floor tray

Floor Surface Anti-slip Karari pattern

Inner insulating cushion Urethane foam, with noise cancelling function

Outer insulating cushion High strength, polypropylene foam, with noise cancelling function

Base frame Maintains integrity

Composition of FRP panel


Floor type prefabricative pan (example) Wall type prefabricative pan (example)

* Extracted from JIS A 4419:2005 Prefabricative Pans for Bathrooms

FRP Floor tray


DELIVERY OF PBUS TO SITE

Precast concrete cell completed with finished

wall & floor prior to delivery to site

Wall panels and floor tray separately lifted and assembled at site

Wall panels and floor trays pre-assembled

in factory prior to delivery to site

Volumetric concrete PBU

Steel panel wall PBUs

Drywall PBUs

FRP PBU

Lightweight concrete PBU

METHOD OF TRANSPORTATION

Delivering PBUs by use of low-bed trailer

• The lighter the PBU, the easier it is to handle and transport

• Volumetric concrete PBUs might be too heavy , hence are generally installed by critical path only

• Lighter PBUs can be installed by non-critical path

We

igh

t o

f e

ach

PB

U

Ease of handling

TYPICAL WEIGHT OF PBUS & EASE OF HANDLING

Volumetric concrete PBU 3.4 to 9 tonnes

Lightweight concrete PBU 3.5 tonnes

Steel panel wall PBU 2.5 to 8 tonnes

Drywall PBU 2 tonnes

FRP PBU <2 tonnes

Installation of volumetric PBU by slot-in method (Non-critical path)

Installation of volumetric PBU by top down method (Critical path)

METHOD OF INSTALLTION

Requires tower cranes for hoisting of PBU to any storey with structural concrete slab

Transfer PBU to location using equipment e.g. pallet jacks and shifting trolley

Slot-in imethod s usually used for metal panel wall PBU which is generally lighter than volumetric concrete PBUs

For both methods of installation Installation of inaccessible pipes before PBU installation Other services to be connected outside or through the ceiling Installation of PBUs on site is followed by watertightness tests , pipe pressure tests and final

inspections

Requires tower cranes for hoisting PBU to the topmost storey with structural concrete slab

PBUs can either sit on top of structural slab or corbel

Critical path installation usually for heavier volumetric concrete PBUs

Corbel to support PBU (Single slab approach)

Corbel for PBU to sit on

PBU floor slab which can also act as ceiling of PBU below (Single slab approach; no structural slab)

Source: Sunway Concrete Pte Ltd


Diagram shows typical sectional detail of PBU sitting on corbel

PBU

Structural slab to support PBU (Double slab approach)


Source: Yau Lee Holdings Limited

Non-structural wall might be covered by drywall board


Gap between top edge of PBU and structural slab of above unit can be covered with drywall board.

Tapered edge in PBU wall to receive drywall board

Installation of panelised PBUs by assembly on site


Delivered to sites as pallets of panels

Wall, floor & ceiling panels are prefabricated in factory

Structural floor, wall and ceiling ready for installation of panels

No waterproofing required

“LEGO” Installation System

Commonly used in Japan e.g. TOTO, Lixil

Adopted in Singapore at Wilby Central , Trellis Tower

Japan’s FRP PBU system, Spiritual Mode, is adopted for apartment units at Wilby Central

FACTORY PRODUCTION OF VOLUMETRIC CONCRETE / LIGHTWEIGHT CONCRETE PBU

1. Casting of concrete shell 2. Curing of concrete and storage

3. Laying of waterproofing system to floor and wall

4. Tiling

FACTORY PRODUCTION OF VOLUMETRIC CONCRETE / LIGHTWEIGHT CONCRETE PBU

7. Completed unit

5. Installing finishes and fittings 6. Quality checks

INSTALLATION OF VOLUMETRIC CONCRETE / LIGHTWEIGHT CONCRETE PBU ON SITE

8. Completed units are ready for delivery

9. Transporting PBUs to site 10. Hoisting of PBU

INSTALLATION OF VOLUMETRIC CONCRETE / LIGHTWEIGHT CONCRETE PBU ON SITE

11. Preparation to receive the PBU

12. Hoisting of PBU into location

13. Final adjustment

FACTORY PRODUCTION OF STEEL PANEL WALL PBU

1. Forming of mould - Pre-bend galvanised steel sheet according to dimensions of PBU

2. Provision of reinforcement and cast-in services in the mould

3. Casting of PBU floor slab 4. Application of cementitious waterproofing membrane


5. Erection of steel panel walls with pre-laid tiles

6. Cementitious waterproofing upturn at floor and wall joints

7. Installation of hot and cold water piping

7. Closing of ceiling boards with provision of ceiling panels

6. Close co-ordination for installation of cabinet, sanitary wares, mirror, solid surface and shower screens


TRANSPORTATION AND STORAGE OF PBUS

7. Transportation of PBUs using low-bed trailer

INSTALLATION OF STEEL PANEL WALL PBUS ON SITE

7. Hoisting of PBUs to floor

8. Shifting PBU to its location for installation

9. Final connections to main services on site

VIDEO CLIP: HOISTING PBU INTO POSITION

• By chiselling

• By heating

OR

For replacement of tiles in steel panel wall PBUs

or: By Overlay

METHOD OF MAINTENANCE

For tiles bonded to wall using adhesive

For tiles bonded to wall using cementitious mortar

• Replacement of pipes through false ceiling, access panel or back of the wall panel

• Replacement of corroded metal panels by cutting out the damaged parts

Replacement of services/panels in metal panel wall PBU METHOD OF MAINTENANCE, REPAIR & REPLACEMENT

PROS & CONS OF EACH TYPE OF PBU Volumetric concrete PBU


Steel Panel Wall PBU

Drywall PBU FRP PBU

Durability and highest service life

√√√√ Similar to

conventional

bathroom


conventional

bathroom

√√ Steel panels

might corrode

after some

time

√√√ Drywall

panels are

less

susceptible

to corrosion

√ Panels could

last at least 20

years (Based

on Lixil’s

system)

Least difficulty in handling and transportation

√ ~3.4 to 9

tonnes (c/w

finishes); less

ductile hence

floor/wall

cracks more

easily

√√

3.5 tonnes

(c/w

finishes);

less ductile

hence

floor/wall

cracks more

easily

√√√

~ 2.5 to 8

tonnes (c/w

finishes);

more ductile

hence

floor/wall less

susceptible to

cracks; Tiles

might crack if

applied with

epoxy glue

√√√√

2 tonnes

(c/w

finishes);

Tiles might

crack if

applied with

epoxy glue

√√√√√

Panels are

lightweight;

possible to flat-

packed.

However,

panels might

need to be

made stronger

to resist

warping during

hoisting.




Drywall PBU FRP PBU

Highest strength and robustness


conventional

bathroom


convention

al

bathroom

√√ 100kg

cantilever

load can be

supported on

a 2mm thk

steel panel

√√√ 50kg to 60kg

cantilever load

can be

supported,

depending on

drywall

system used

√ 20kg cantilever

load can be

supported

Least difficulty in installation on site

√√√√ Usually by

critical path

installation;

Needs

hoisting by

cranes;

√√√√ Critical or

non-critical

path (slot-

in)

installation

√√√ Critical or

non-critical

path (slot-in)

installation

√√ Critical or non-

critical path

(slot-in)

installation

√ Critical or non-

critical path (slot-

in) installation; can

be delivered to

site in panels with

necessary

openings and assembled on site

PROS & CONS OF EACH TYPE OF PBU




Drywall PBU FRP PBU

Least efforts to ensure water tightness

√√√√ Volumetric

casting

hence no

joints for

leakages to

occur

√√√√ If volumetric

casting,

there should

be no joints

for leakages

to occur; if

assembly of

substructure

s (e.g. L-

shaped

panels),

water

proofing is

critical at

joints

√√√ Water

proofing is

critical at

joints of wall

to floor and

wall to wall;

chances of

water

proofing

membrane

being

damaged

by retiling,

drilling or

cutting

works

√√ Water proofing is

critical at joints

of wall to floor

and wall to wall;

Board used

should be

moisture

resistant and

applied with

water proofing

membrane;

chances of water

proofing

membrane being

damaged by

retiling, drilling or

cutting works

√ Joints of wall to

floor and wall

wall should be

covered with

gaskets and

applied with

silicon sealant;

chances of

water seepages

through panels

or joints after

drilling or cutting

works





Drywall PBU FRP PBU

Least difficulty in installation on site

√ Heavy; Usually by critical path installation only

√√√ Slightly lighter; Critical or non-critical path (slot-in) installation

√√√ Lightweight; Critical or non-critical path (slot-in) installation

√√√√ Lightweight; Critical or non-critical path (slot-in) installation

√√√√ Critical or non-critical path (slot-in) installation; assembly on site is possible

Most familiar to renovators in maintenance, replacement / renovation works

√√√√ Similar to conventional bathroom

√√√√ Similar to conventional bathroom

√ Cannot use conventional method of using chisel and hammer; heating is required to remove tiles

√√√ May use conventional method of chisel & hammer to remove tiles & cutter to create openings in board to replace piping; Easy to patch opening

√√ Affected panel can be removed to access pipes behind for replacement; alternatively, the entire PBU can be changed.


Overview


Design Fabrication Assembly, finishing & fitting out

Transportation & storage

Installation on site

PBUs handed over to

homeowners

Maintenance, repair and

replacement

PBU – FROM DESIGN STAGE TO HOMEOWNERS’ USE

Design for fabrication

Design for functionality

Design for productivity

Design for installation

Design for replacement

A good PBU design should provide practical solutions to address potential issues arising in different stages of PBU’s lifecycle.

PBU design considerations

Architectural

Potential challenges

during installation

Subsequent maintenance

challenges Structural

Technical Specifications

OVERVIEW OF PBU DESIGN CONSIDERATIONS

GOOD DESIGN REQUIREMENT AND FRAMEWORK

From Sep 2014 onwards, it will be mandatory to use Prefabricated Bathroom Units (PBU) in non-landed residential Government Land Sale (GLS) sites

The Land Sales’ conditions as well as the Regulations and Code of Practice on Buildability will be amended to reflect this mandatory requirement for PBUs

MANDATORY TO USE PBUS

Overview of PBU Performance Requirement

1. Definition of PBU 2. Strength and Robustness of Wall Panels 3. Access to Utilities for Maintenance, Repair and

Replacement 4. Replacement of Tiles 5. Provision for Barrier-Free Accessibility

Requirements 6. Manufacturer’s Label 7. Homeowner User Manual

Definition of Prefabricated Bathroom Unit (PBU)

1 Prefabricated Bathroom Unit (PBU)

A prefabricated bathroom unit refers to a bathroom unit preassembled off-site complete with finishes, sanitary wares, concealed pipes, conduits, ceiling, bathroom cabinets and shower screen before installing in position

Strength and Robustness of Wall Panels

2 Strength and Robustness of Wall Panels (a) For PBU with wall panels manufactured with non- concrete or lightweight concrete materials, the wall panels are to be tested in accordance with the Specification for performance requirements for strength and robustness (including methods of test) for partition walls – SS492:2001 to achieve a minimum grade of Medium Duty.

Strength and Robustness of Wall Panels (cont.)

• Description of Strength Grades in accordance with SS492:2001

Strength and Robustness of Wall Panels

2 Strength and Robustness of Wall Panels (b) The wall panels should not be susceptible to corrosion in the long term

Access to Utilities – Vertical Soil Stack

3 Access to Utilities for Maintenance, Repair and Replacement (a) The vertical soil stack shall be located such that it is readily accessible from outside the PBU and within the dwelling unit or from the common areas of the same floor

Access to Utilities – Ceiling Access Panels

3 Access to Utilities for Maintenance, Repair and Replacement (b) Access panels must be provided at the ceiling within

the PBU to provide access for maintenance, repair and replacement of overhead services and utilities.

Replacement of Tiles

4 Replacement of Tiles The PBU must allow for tile replacement to be done via

hacking with chisel and hammer, or their equivalent tools, without resulting in damage to the wall panels or backing board.

Provision for Barrier-Free Accessibility Requirements

5 Provision for Barrier-Free Accessibility Requirements (a) For PBU with wall panels manufactured with non-concrete

or lightweight concrete materials, provision shall be made on the wall panels for future installation of grab bars in the PBU.

(b) Information such as the location for future installation of grab bars and the installation method statement shall be included in the homeowner user manual (see item 1.9.7).

Provision for Barrier-Free Accessibility Requirements (cont.)

Photo for illustration only

Manufacturer’s Label

6 Manufacturer’s Label

A manufacturer’s label measuring 6cm by 10cm of a waterproof and rustproof material is to be affixed within the PBU with the following information on it:

a) Date of manufacture in the following format: Month/Year b) Name of manufacturer c) Company address of manufacturer d) Contact number of manufacturer e) Material of wall panel f) Material of floor pan

Manufacturer’s Label (cont.)

10cm

6cm

Name of Manufacturer

Company Address and Contact Number

Date of Manufacture: MM/YYYY Material of Wall Panel Material of Floor Pan

Homeowner User Manual

7 Homeowner User Manual A user manual containing the following information shall be provided to homeowners upon the handing over of the unit:

Requirement on Homeowner User Manual

• To be included in the Building Maintenance and Strata Management Act (BMSMA)

• To include a clause in the Sales & Purchase (S&P)

Agreement that entails Developers to provide a copy of the Homeowner User Manual to homeowners upon handing-over of unit

Proposed Framework for Acceptance of PBU Systems

cleared

Ok

Applicant submits proposal for PBU system which meets Performance Requirements

BIP

(other regulatory

authorities)

Building Innovation Panel (BIP)

BCA

(Screening Panel) The condition for acceptance includes the accreditation of manufacturer under the PBU Manufacturer Accreditation

Scheme

PBU systems which are accepted by the BIP will be listed on the BCA website

QPs using the accepted PBU systems can score Buildability Points

Proposed Framework for Existing/New PBU Systems

The following will be announced through a circular/advisory note to the industry:

• Building Innovation Panel (BIP) PBU Screening Panel – chaired by BCA and industry

reps Other regulatory authorities (e.g. SCDF, PUB, NEA

etc)

• PBU Manufacturer Accreditation Scheme (PBU MAS) – to accredit the production process and plant facilities for the PBU systems

2. Building Innovation Panel (BIP)

Inter-agency panel to assist firms in receiving fast multi-agency evaluation of innovation methods, processes and materials that would improve construction productivity significantly

A certificate of In-Principle Acceptance (IPA) will be granted if acceptances are obtained from the relevant participating authorities and agencies

CHAIR

DS(ND) and CEO(BCA)

BCA MOM PUB SCDF URA LTA NEA HDB JTC

SECRETARIAT

CPC (BCA)

2. Building Innovation Panel (BIP)

1. PBU Screening Panel (Proposed Areas of Assessment)

• Ease of assembly & installation

• Fully prefinished and prefitted off-site Design for Productivity

• Suitability of materials (wall, floor, ceiling etc)

• Location of services/vertical stack/maintenance panel

• Provision for BFA requirements

• Flexibility in layouts due to project requirements

• Methods for watertightness tests (e.g. pipe joints, wall-to-wall and wall-to-floor joints)

• Typical details (shop-drawings to be provided)

Design for Functionality

• QC checklist and standard

• Training for installers/renovators

• Suitability of lifting details

Design for Fabrication/Installation

• Provision & method statement for maintenance / renovation / replacement

• User Manual for homeowners Design for Replaceability


Architectural

PBU DESIGN CONSIDERATIONS – ARCHITECTURAL

Required bathroom’s strata area Wall thickness of PBUs ranges from 50 mm to 150

mm, depending on the system.

There might be double walls (PBU wall and building’s external wall) at the side with windows.

Designers should take into consideration the required bathroom’s strata area due to installation of PBUs during their selection of PBU systems.

PBU DESIGN CONSIDERATIONS – ARCHITECTURAL

Treatment to the drop in soffit level of the slab A drop at the entrance of bathroom is incorporated to

contain water within the bathroom for most residential developments

Alternatively, a kerb may be provided at the bathroom’s entrance to avoid creating a separate floor level

Illustration of drop in soffit level of the slab for traditional cast-in situ concrete bathroom

Illustration of kerb ‘s location for traditional cast-in situ concrete bathroom

PBU DESIGN CONSIDERATIONS- ARCHITECTURAL

Location of service ducts and access panel for maintenance The routing and connection of services have to be

predetermined and coordinated with PBU supplier

Vertical soil stack should be accessible for future maintenance, repair and replacement

Photograph shows example of a vertical soil stack which is accessible from within the dwelling unit. Such location allows connection sanitary pipe from below PBU.


Location of service ducts and access panel for maintenance

Layout plan of a typical storey in a private residential project

Vertical stack is accessible for future maintenance from A/C ledge or another room

Figure 2 – Example of a layout of a prefabricated bathroom unit with a services shaft

that is accessible for future repairs and maintenance

(based on Code of Practice on Buildability Sep 2013)





3 Bedroom + Study



4 Bedroom



Access to vertical soil stack within dwelling unit


HDB Project Sengkang N4 C24/C25

• Typical 3-Room Flat


HDB Project Sengkang N4 C24/C25

• Typical 4-Room Flat

Location of PBU on floor plan Important to facilitate hoisting of PBU into the building

Requires detailed study into the building layout, site boundary, constraints, etc

Ensures that no beam is obstructing the path of PBU installed via slot-in method


PBU DESIGN CONSIDERATIONS- ARCHITECTURAL Location of PBU on floor plan (Cont’d) Important to consider how PBUs can access the required

positions based on the possible locations of tower cranes, especially for slot-in method

Problem for PBU to be pushed to

this location if go by slot-in method

Layout plan of a typical storey in a private residential project

Position of

tower crane

PBU DESIGN CONSIDERATIONS- ARCHITECTURAL Location of PBU on floor plan (Cont’d) Example of how location of PBUs will affect position of tower cranes used

to hoist PBUs onto required level

Tower crane position

Legend

PBU Indication of locations of PBUs

PBU DESIGN CONSIDERATIONS- ARCHITECTURAL Performance of Wall Panels Floor and wall panelling systems of some PBUs might sound

hollow

Find out whether the suppliers can reduce the sound of hollowness

Different components of a prefabricated bathroom

PBU DESIGN CONSIDERATIONS- ARCHITECTURAL Types of finishes for the wall and floor Some PBU systems do not encourage the use of tiled finishing

Designers need discuss their requirements with PBU suppliers before choosing a PBU system

For example, in COZY SUZHOU bathroom pod which uses Sheet Moulded Compound (SMC) as wall panel, there is no need for tiles as the wall panels come with laminated finish .


Design of Secondary Slab As a provision for drainage when leakages occurred, the

secondary slab to receive PBU should be cast with a gradient and an opening at the lowest point so that any water would drip through the opening and could be noticed by the owner of the apartment unit below


Preventing breakages of glass shower screen Glass shower screen can withstand against breakages due to

vibrations during transportation breaking, if designed with adequate supporting structures within the PBUs

Such supporting structures can be U-frame on top of the glass shower screen

Structural


PBU DESIGN CONSIDERATIONS- STRUCTURAL

Weight of PBU & associated loads Design for secondary slab (structural slab) should cater for the

following weights:-

Weight of PBU

Loading of temporary props, if they are used outside PBU for installation purpose

Secondary slab (structural slab)

PBU


Method of hoisting Recommended for points of lifting to be from bottom of PBUs

for better stability

Structure of PBUs may have to be strengthened or modified, if there are restraints by final location of PBUs on the method of hoisting or points of lifting

Lifting anchors at bottom of PBU


Adoption of flat plate system To avoid PBUs being obstructed by beams, flat plate system

could be considered if installation of PBU is by slot-in method

Flat plate with circular steel column PBUs installed via slot-in method should not face obstruction e.g. beams

PBU DESIGN CONSIDERATIONS- STRUCTURAL Future provision of grab bars in PBUs Under Barrier-Free Accessibility Act , there shall be at least one

bathroom in every residential unit that can be retrofitted for the elderly persons and wheelchair users when the need arises

For PBU with walls manufactured in non-concrete or lightweight concrete material, reinforcement might be required for future installation of grab bar

Back plate can be added behind wall of drywall type PBU to act as reinforcement for grab bars

Grab bar

Technical Specifications


PBU DESIGN CONSIDERATIONS- TECHNICAL SPECIFICATIONS

• SS492:2001 Strength and robustness for Partition Walls

• Waterproofing CP82

• CONQUAS 21

• Water absorption test, BS 1881-122:2011

• COP for Water Services, SS CP 48

• COP for Sewerage and Sanitary Works

• Mechanical ventilation

• Mold resistance ASTM D3273-12

• Fire resistance tests

• Sound acoustic test ASTM-E90 ISO 140 Part 3

Others M&E

Structural & Robustness

Waterproofing

Productivity Gains, Time & Resource Management

5892.6

6826.4

26559

0

5000

10000

15000

20000

25000

30000

Steel Panel Wall PBU Conventional Cast in-situ Bathroom

Man

day

s re

qu

ire

d f

or

pro

ject

Mandays required on site

Mandays required in factory

PRODUCTIVITY GAINS

Total 12719 mandays required for 644 nos of

steel panel wall PBU

Savings in mandays:

52%


conventional cast in-situ bathrooms

19.75 manday/bathroom 41.24 manday/bathroom

Saves 21.41 manday/bathroom Manday comparison in local project using

steel panel wall PBU

1627.5

387.5

3817.65

0

500

1000

1500

2000

2500

3000

3500

4000

4500

Volumetric concrete PBU Conventional Cast in-situBathroom

Man

day

s re

qu

ire

d f

or

pro

ject

Mandays required on site

Mandays required in factory

PRODUCTIVITY GAINS


volumetric concrete PBU

Savings in mandays:

47%

Total 3817.65 mandays required for 310 nos of

conventional cast in-situ bathrooms

6.5 manday/bathroom 12.32 manday/bathroom

Saves 5.78 manday/bathroom Manday comparison in local project using

volumetric concrete PBU

TIME & RESOURCE MANAGEMENT - BENEFITS

Site installation and fabrication of PBUs in factory can run parallel Entire PBU can be produced in the factory without affecting

site operations, thereby shortening the construction cycle and construction period

Downtime is minimised as production of PBUs can continue during times of inclement weather

Example of how structural works and PBU fabrication can run parallel


Better control of materials and prefabrication process in the factory Results in higher quality finishes and lower wastage of

materials


Liability of various trades on one party only The various trades involved in the wet area (tiler, plumber,

electrician and waterproofing applicator) are made the responsibility of one party, reducing chances of error due to lack of coordination


Lesser abortive works are anticipated on site Construction program should allocate more time for

planning and design before structural works and PBU fabrication begin

Designers might need to grapple upfront with issues for works e.g. selection of architectural finishes that usually happen in later phases for conventional projects


Streamline of Work Processes Workers in various trades such as tiling, plumbing, electrical

works, waterproofing application etc can move laterally from one PBU to another, thereby maximising their working hours by reduction of idle time

Compared to conventional bathroom construction, delays and waiting time easily occur due to unforeseen circumstances or poor planning on site

Steep learning curve for designers, project managers and builders Due to different architectural, structural and MEP

considerations and sequence of works for projects using PBUs Detailed planning and project development is important to

ensure success in PBU adoption

TIME & RESOURCE MANAGEMENT - RISKS

Possible damage or vandalism by third party on site PBU suppliers might need return a few times to project site to

reinstate defects caused by third party Repair works might be costly; Builders / PBU suppliers run the

risks of bearing the costs Recommendations: Lockable PBUs, comprehensive protection

on the interior and external of PBUs, strict housekeeping rules

TIME & RESOURCE MANAGEMENT - RISKS

INTRODUCTION ON PBU ACCREDITATION SCHEME

PBU Manufacturer Accreditation Scheme

Accreditation of production process and plant/facilities to ensure quality of the system

Accreditation Criteria:

• Training & Quality Management System (QMS) • Plant Facilities & Design Capabilities • Quality Control (QC) in Production • Storage, Delivery, Installation & Maintenance • Corrective & Preventive Actions

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