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📋 Part of our Curtain Wall Guide

Related: Curtain Wall vs Window Wall · Curtain Wall Installation

A glass curtain wall Singapore project is not specified simply by choosing glass and an aluminium frame.

The façade has to manage several conditions at once: intense solar radiation, high humidity, frequent heavy rainfall, wind-driven rain, cooling loads, structural movement and long-term exposure.

The glazing controls much of the solar and thermal performance. The aluminium frame supports the glazing and transfers structural loads. The curtain-wall joints, gaskets and drainage system control air and water movement.

For Singapore projects, these elements need to be designed as one façade system.

The current SS 654:2020+A1:2023 — Code of Practice for Curtain Walls specifies materials and performance requirements for metal-framed curtain walls and provides requirements and good practices for design and installation. Its performance framework includes air permeability, watertightness and structural performance, and covers components such as brackets, anchors, flashings, gutters and copings.

The practical specification sequence is:

Glazing → Solar Control → Thermal Performance → Structure → Air → Water → Drainage → Installation → Testing

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Quick Summary

The short version: a glass curtain wall Singapore project should be specified as an integrated façade system, not as a collection of glass panels.

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Why a Glass Curtain Wall Is a System, Not a Pane of Glass

A curtain wall may look like a continuous glass surface, but the visible glass is only one part of the assembly.

A complete façade can include:

• insulated glass units
• mullions
• transoms
• pressure plates
• gaskets
• structural silicone where applicable
• thermal-isolation components
• brackets
• anchors
• flashings
• gutters
• drainage channels
• weep paths

Changing one component can influence another.

For example, changing the glazing can change:

• panel weight
• solar heat gain
• thermal performance
• acoustic performance
• structural requirements

Changing the frame can influence:

• sightlines
• glass size
• thermal bridges
• drainage
• structural capacity

Changing a joint detail can influence:

• air leakage
• water penetration
• movement
• durability

That is why glass curtain wall systems should be engineered as complete assemblies.

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Why Singapore Changes the Curtain Wall Specification

A Singapore façade has a different thermal problem from a cold-climate façade.

The main concern for an air-conditioned building is generally not winter heat loss. It is the combined effect of:

solar heat gain + conductive heat transfer + window-to-wall ratio + shading + cooling load.

BCA’s Code on Envelope Thermal Performance for Buildings defines ETTV as an envelope-level measure that accounts for heat conduction through opaque walls, heat conduction through glass windows and solar radiation through glass windows. The published method uses factors including window-to-wall ratio, fenestration thermal transmittance and shading characteristics.

That means a curtain wall can have good centre-of-glass performance but still contribute to a poor envelope result if:

• the solar-control strategy is weak
• the glazed area is excessive
• external shading is inadequate
• the frame creates significant thermal transfer
• façade orientation is unfavourable

So the question is not:

“Does this curtain wall have a U-value of 1.8?”

The better question is:

“Does this complete façade configuration satisfy the project’s thermal and solar-performance requirements?”

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1. Glazing Build: Start With the Glass Package

A typical glass curtain wall Singapore project may use insulating glass units with:

• two panes
• an insulating cavity
• Low-E or solar-control coating
• air or argon fill where specified
• a defined spacer
• heat-treated or laminated glass where required

But 6 + 12A + 6 Low-E is not a complete glazing specification.

The procurement schedule should define:

The correct glass is therefore a project decision, not a universal “best curtain-wall glass”.

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2. Solar Control Is Critical in Singapore

Large glazed façades can introduce substantial solar heat into air-conditioned buildings.

For Singapore projects, specify solar-control performance together with thermal performance.

The façade strategy may include:

• solar-control Low-E
• selective coatings
• external shading
• reduced solar-exposed glazing
• appropriate window-to-wall ratio
• glass with controlled visible transmittance

BCA’s ETTV methodology explicitly accounts for solar radiation through glazing and uses shading-related factors in the calculation.

Therefore:

Low-E alone is not a complete Singapore solar-control specification.

The project may need to balance:

solar heat gain + daylight + glare + visible light + façade appearance + thermal performance.

This is especially important for highly glazed office, hotel and commercial façades.

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3. Thermal Performance: Don’t Use One Universal U-Value

The original practice of using:

U-Factor ≤1.8 W/m²·K

as the universal curtain-wall target should be avoided.

The complete façade contains:

glass + frame + spacer + joints + thermal bridges + shading + façade geometry.

BCA’s envelope methodology evaluates thermal performance at the building-envelope level rather than treating the glazing as an isolated component. The ETTV calculation explicitly combines opaque wall and fenestration contributions.

For projects pursuing Green Mark, façade thermal performance can also contribute to the overall energy-performance strategy.

BCA states that Green Mark 2021 is tailored to Singapore’s tropical climate and applies to new and existing commercial, industrial, institutional and residential buildings. The current second edition has been effective from 1 January 2024, with all projects assessed under the second-edition documents from 1 June 2024.

The correct procurement question is therefore:

What glazing and framing combination allows the building to meet its project ETTV and energy-performance requirements?

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4. Water Management: Drainage Matters More Than More Sealant

A Singapore curtain wall is exposed to intense rainfall and wind-driven rain.

The goal is not simply to make every joint permanently watertight with sealant.

The system should provide controlled paths for water management through:

• gaskets
• joints
• internal drainage channels
• gutters
• weep paths
• flashings
• pressure-management zones
• perimeter interfaces

SS 654:2020+A1:2023 specifically includes watertightness in its performance framework and covers gutters, flashings and other components required for proper curtain-wall construction.

The wrong approach is:

Add more sealant until the leak disappears.

The correct approach is:

Identify the water-management path, maintain the drainage design, verify the joints and test the completed system.

A failed drainage path cannot reliably be fixed by adding sealant to the visible exterior joint.

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5. Air Permeability

Air leakage affects more than indoor comfort.

It can influence:

• cooling demand
• façade pressure
• water behaviour
• indoor comfort
• durability

SS 654 includes air permeability within its curtain-wall performance testing framework.

For a Singapore project specification, define the required air-performance level and the applicable testing procedure under the project documentation.

Avoid importing North American numbers such as:

0.07 CFM/ft²

unless the project contract specifically requires that test framework.

For Singapore projects, the specification should start from:

project requirement → applicable SS 654 performance framework → tested system → documented result.

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6. Structural Performance

A curtain wall has to carry the loads imposed on the façade system while accommodating movement between the building and the curtain wall.

The structural design may consider:

• wind pressure
• suction
• mullion span
• transom span
• panel dimensions
• glass weight
• anchor positions
• bracket capacity
• building movement
• thermal movement

SS 654 covers structural performance of metal-framed curtain walls.

Do not use:

±75 psf

as a universal Singapore specification.

The required wind performance should come from the project’s structural design.

The structural calculation should correspond to the actual:

panel size + glazing build + mullion/transom geometry + anchor configuration.

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7. Safety Glazing

Curtain-wall glass can occur in areas where human impact is possible.

Singapore’s SS 653:2020 provides requirements for glazed components that may be subject to human impact and is intended to guide designers and installers in reducing injury risk.

The glass specification should therefore consider:

• location
• human-impact risk
• glass type
• heat treatment
• laminated construction
• adjacent circulation
• doors and entrances
• sill height
• project requirements

Do not simply write:

“Tempered glass throughout.”

The required safety solution depends on the application.

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8. Structural Glazing

Structural glazing should not be treated as simply a frameless version of a conventional curtain wall.

Where structural silicone glazing is used, the specification needs to address:

• silicone compatibility
• glass/coating compatibility
• substrate preparation
• primer requirements
• bond geometry
• curing
• adhesion
• quality-control procedures

The bonding process should be supported by the applicable project and manufacturer documentation.

For structural sealant glazing, ISO 28278-2 provides assembly and quality-control guidance for structural sealant glazing applications.

The correct specification is therefore:

glass + silicone + substrate + preparation + geometry + curing + QC

rather than:

“Use structural silicone.”

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The Singapore Curtain Wall Performance Matrix

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Don’t Confuse Glass Performance With Curtain-Wall Performance

This is one of the most important procurement points.

A glass supplier might provide:

Ug = X

That is the thermal performance of the glazing component under its applicable calculation method.

It is not automatically the thermal performance of the curtain wall.

Likewise:

SHGC = X

does not mean the building façade automatically has the same solar performance.

The complete façade includes:

glass area + frame area + thermal bridges + shading + orientation + window-to-wall ratio + installation.

That is why BCA’s ETTV methodology works at the envelope level.

A proper specification should connect:

glass data → façade calculation → building-envelope performance.

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Glass Curtain Wall System Specification for Singapore

This is much more useful for an RFQ than simply specifying:

“6 mm + 12A + 6 mm Low-E curtain wall.”

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Singapore Green Mark and Glass Curtain Walls

Green Mark should not be treated as a window certification.

BCA describes Green Mark 2021 as an internationally recognised green-building certification scheme tailored to the tropical climate. The scheme applies to new and existing commercial, industrial, institutional and residential buildings.

For façade design, the curtain wall can influence:

• envelope thermal performance
• solar heat gain
• cooling demand
• maintainability
• embodied-carbon considerations
• resilience

For Green Mark projects, the façade specification therefore needs to remain traceable from:

design calculation → tender specification → approved material → installed façade.

BCA’s current environmental-sustainability framework provides ETTV/RETV calculation formats and requires relevant project documentation for environmental-performance assessments.

One important current-date consideration is that BCA has also published newer Green Mark certification requirements for future application periods, so the project team should verify which certification standard applies to the project’s application date rather than assuming every Singapore project uses the same edition.

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Water-Management QC Checklist

Before the curtain wall is closed and handed over, verify:

• Drainage channels are continuous
• Weep paths are unobstructed
• Gaskets are correctly seated
• Pressure-management paths are complete
• Flashings are coordinated
• Perimeter seals are correctly prepared
• Joints accommodate movement
• Interfaces are documented
• Required testing is completed
• Failed areas are repaired and retested

The critical principle is:

water management is a designed system, not a sealant quantity.

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What to Request From a Singapore Curtain-Wall Manufacturer

For a professional Singapore project, request:

• system sections
• mullion/transom details
• glass schedule
• IGU specification
• Low-E/solar-control data
• thermal calculations
• ETTV project input data where applicable
• structural calculations
• anchor/bracket details
• SS 654 performance/test evidence
• drainage details
• sealant and gasket schedule
• structural-glazing compatibility data where applicable
• finish specification
• installation method statement
• inspection and test plan
• shop drawings
• as-built documentation

For Green Mark projects, also maintain the material information needed for the project energy and envelope calculations.

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Decision Guide: Which Glass Curtain Wall Strategy?

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Frequently Asked Questions

What is a glass curtain wall in Singapore?

A glass curtain wall is a non-load-bearing building-envelope system consisting of glazing, aluminium framing and associated components such as anchors, gaskets, flashings and drainage elements. In Singapore, SS 654:2020+A1:2023 provides the current code-of-practice framework for metal-framed curtain walls.

What glazing is normally used in glass curtain wall systems?

Insulating glass units with Low-E or solar-control coatings are common, but the correct build depends on the project’s thermal, solar, structural, acoustic and safety requirements.

Is double glazing enough for a Singapore curtain wall?

Not necessarily. Singapore’s cooling-dominated climate makes solar heat gain a major façade consideration. Glazing should be assessed together with shading, window-to-wall ratio and the overall envelope strategy. BCA’s ETTV methodology includes heat conduction and solar radiation through glazing.

What U-value should a glass curtain wall have in Singapore?

There is no single universal U-value that applies to every Singapore curtain wall. The project should establish the required thermal performance using the applicable envelope-performance method, including ETTV where applicable.

How does a glass curtain wall manage water in Singapore?

Through coordinated gaskets, joints, internal drainage channels, gutters, weep paths and perimeter interfaces. SS 654 specifically includes watertightness within its performance framework and covers associated façade components needed for proper construction.

What standard applies to curtain walls in Singapore?

SS 654:2020+A1:2023 is the current Singapore Code of Practice for curtain walls. It covers materials and performance requirements and provides requirements and good practices for design and installation of metal-framed curtain walls.

What safety-glazing standard applies in Singapore?

SS 653:2020 provides requirements and guidance for glazed elements that may be subject to human impact. The actual application should be checked against the project location and applicable regulatory requirements.

Are glass curtain walls suitable for Singapore’s tropical climate?

Yes, but the specification needs to be climate-specific. Solar heat gain, cooling loads, heavy rainfall, water drainage, humidity, structural loads and maintenance should all be considered.

What is structural glazing?

Structural glazing uses structural sealant as part of the attachment of glass to the supporting frame or carrier. It requires controlled surface preparation, compatibility verification, correct bond geometry, curing and quality control.

Do glass curtain walls need thermal breaks?

The frame needs an appropriate thermal design for the project. A thermal break or thermal-isolation configuration can reduce heat transfer through aluminium framing, but the complete façade performance must still be evaluated.

What should I ask a Singapore curtain-wall manufacturer for?

Request system drawings, glass schedules, solar and thermal data, structural calculations, SS 654 test/performance evidence, drainage details, installation drawings, sealant/gasket specifications and project-specific shop drawings.

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Bottom Line

The best glass curtain wall Singapore projects are not specified by choosing a glass build and adding an aluminium frame.

They are engineered as a complete façade:

Glazing → Solar Control → Thermal → Structure → Air → Water → Drainage → Safety → Installation → Testing

For Singapore, solar control deserves particular attention because the BCA envelope methodology evaluates heat conduction and solar radiation through the building envelope rather than looking at glass U-value in isolation.

For curtain-wall construction, SS 654:2020+A1:2023 provides the current Singapore framework for metal-framed curtain walls and covers air permeability, watertightness and structural performance as well as associated brackets, anchors, flashings, gutters and other components.

For buildings pursuing Green Mark, the façade also forms part of a broader tropical-climate energy and sustainability strategy. BCA’s current Green Mark 2021 framework is the second edition for projects under the current scheme, while applicable projects should verify which Green Mark certification standard applies to their application date.

The most important procurement rule is:

Do not compare glass performance, frame performance and curtain-wall performance as if they were the same number.

Specify the complete system and require evidence for the actual configuration.

Request a Glass Curtain Wall Specification →