performance requirements for pbus in gls sites€¦ · performance requirements for pbus in gls...
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Introduction on PBUs
Considerations for Good PBU Design
Good design requirement and framework
Productivity Gains, Time and Resource Management
• 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
Concrete floor / Steel wall
The Oceanfront @ Sentosa
Cove, One Shenton, Livia,
Wilkie Studio, Shelford Suites
Concrete floor/ concrete wall
Cliveden @ Grange
Concrete floor / Steel wall
NV Residences, Hundred
Trees, Tree House, The
Glyndebourne
Concrete floor/ concrete wall
The Arte @ Thomson,
Quayside W Residences @
Sentosa Cove, Cube 8, 368
Thomson
Concrete floor / Steel wall
Haus @ Serangoon Garden,
Up @ Robertson Quay, Lush
Acres
Concrete floor/ concrete wall
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:-
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)
MATERIALS AND STRUCTURE
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
MATERIALS AND STRUCTURE
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
MATERIALS AND STRUCTURE
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
MATERIALS AND STRUCTURE
Floor type prefabricative pan (example) Wall type prefabricative pan (example)
* Extracted from JIS A 4419:2005 Prefabricative Pans for Bathrooms
FRP Floor tray
MATERIALS AND STRUCTURE
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
• 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
METHOD OF INSTALLTION
Diagram shows typical sectional detail of PBU sitting on corbel
PBU
Structural slab to support PBU (Double slab approach)
METHOD OF INSTALLTION
Source: Yau Lee Holdings Limited
Non-structural wall might be covered by drywall board
METHOD OF INSTALLTION
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
METHOD OF INSTALLTION
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
FACTORY PRODUCTION OF STEEL PANEL WALL PBU
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
FACTORY PRODUCTION OF STEEL PANEL WALL PBU
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
• 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
Lightweight concrete PBU
Steel Panel Wall PBU
Drywall PBU FRP PBU
Durability and highest service life
√√√√ Similar to
conventional
bathroom
√√√√ Similar to
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.
Volumetric concrete PBU
Lightweight concrete PBU
Steel Panel Wall PBU
Drywall PBU FRP PBU
Highest strength and robustness
√√√√ Similar to
conventional
bathroom
√√√√ Similar to
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
Volumetric concrete PBU
Lightweight concrete PBU
Steel Panel Wall 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
PROS & CONS OF EACH TYPE OF PBU
Volumetric concrete PBU
Lightweight concrete PBU
Steel Panel Wall PBU
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.
PROS & CONS OF EACH TYPE OF PBU
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
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).
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
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.
PBU DESIGN CONSIDERATIONS- ARCHITECTURAL
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)
PBU DESIGN CONSIDERATIONS- ARCHITECTURAL
Location of service ducts and access panel for maintenance
PBU DESIGN CONSIDERATIONS- ARCHITECTURAL
Location of service ducts and access panel for maintenance
3 Bedroom + Study
PBU DESIGN CONSIDERATIONS- ARCHITECTURAL
Location of service ducts and access panel for maintenance
4 Bedroom
PBU DESIGN CONSIDERATIONS- ARCHITECTURAL
Location of service ducts and access panel for maintenance
Access to vertical soil stack within dwelling unit
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
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 .
PBU DESIGN CONSIDERATIONS- ARCHITECTURAL
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
PBU DESIGN CONSIDERATIONS- ARCHITECTURAL
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
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
PBU DESIGN CONSIDERATIONS- STRUCTURAL
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
PBU DESIGN CONSIDERATIONS- STRUCTURAL
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
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
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%
Total 26559 mandays required for 644 nos of
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
Total 2015 mandays required for 310 nos of
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
TIME & RESOURCE MANAGEMENT - BENEFITS
Better control of materials and prefabrication process in the factory Results in higher quality finishes and lower wastage of
materials
TIME & RESOURCE MANAGEMENT - BENEFITS
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
TIME & RESOURCE MANAGEMENT - BENEFITS
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
TIME & RESOURCE MANAGEMENT - BENEFITS
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
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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