SS667 - Code of practice for the handling, storage, and processing of combustible dust.

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SS667 – Combustible Dust Safety in Singapore

SS667:2020 is Singapore’s code of practice for the handling, storage, and processing of combustible dust. It provides guidance to prevent and mitigate fire and explosion risks in facilities where fine particulate materials are present.

Combustible dust may appear harmless in solid form, but when dispersed in air under the right conditions, it can ignite rapidly and lead to flash fires or explosions with severe consequences.

This standard outlines how industrial facilities should identify hazards, design systems, and implement controls to manage these risks effectively.

Who SS667 Applies To

SS667 is relevant across a wide range of industries where dust is generated, processed, or handled.

This includes:

  • Manufacturing and general processing industries

  • Pharmaceutical and chemical facilities

  • Food processing plants

  • Metalworking and additive manufacturing

  • Logistics and bulk material handling

The standard applies to facilities that generate, convey, store, or process combustible particulate solids, but typically does not apply to sealed storage where dust is not released during operations.

Understanding Combustible Dust Risk

Combustible dust refers to fine solid particles that can burn or explode when suspended in air.

Examples include:

  • Metal dust (e.g. aluminium, magnesium)

  • Organic dust (e.g. flour, sugar)

  • Chemical dusts

  • Plastic and polymer dust

When these particles are dispersed in the air and exposed to an ignition source, they can result in:

  • Flash fires

  • Explosions

  • Structural damage

  • Injury or fatality

These incidents occur due to a combination of:

  • Fuel (dust particles)

  • Oxygen

  • Ignition source

  • Dispersion (dust cloud)

  • Confinement (enclosed space)

This is often referred to as the dust explosion pentagon.

Key Requirements Under SS667

SS667 outlines a systematic approach to managing combustible dust hazards across the entire facility lifecycle.

1. Hazard Identification

Facilities must determine whether materials handled are combustible or explosible.

This may involve:

  • Reviewing material data

  • Checking Safety Data Sheets (SDS)

  • Conducting laboratory testing where necessary

Even if no incidents have occurred previously, risks must still be assessed.

2. Dust Hazard Analysis (DHA)

A Dust Hazard Analysis (DHA) is a core requirement.

This is a structured assessment used to:

  • Identify fire and explosion scenarios

  • Evaluate likelihood and severity

  • Define required control measures

The DHA must:

  • Be conducted by a competent person

  • Cover all process areas and equipment

  • Be documented and reviewed periodically

This is one of the most critical compliance steps under SS667.

3. Prevention and Mitigation Measures

SS667 requires both preventive and protective controls, including:

Prevention:

  • Elimination or control of ignition sources

  • Minimising dust accumulation

  • Proper housekeeping practices

  • Controlling fugitive dust emissions

Mitigation:

  • Explosion venting or suppression systems

  • Isolation of hazardous processes

  • Fire protection systems

The goal is not just to prevent ignition, but to limit damage if an incident occurs.

4. Equipment & System Design

The standard provides guidance on:

  • Dust collection systems

  • Ducting and conveying systems

  • Air-material separators

  • Process equipment safety

Systems must be:

  • Designed based on material properties

  • Suitable for the specific process

  • Integrated into overall facility safety design

5. Storage & Handling Requirements

SS667 includes requirements for:

  • Bulk storage of combustible materials

  • Handling of fine particulate waste

  • Packaging systems (e.g. containers, bags)

Proper storage is critical to:

  • Prevent dust dispersion

  • Reduce ignition risk

  • Maintain safe operating conditions

6. Safety Management & Maintenance

Beyond system design, facilities must implement:

  • Ongoing inspection and maintenance

  • Worker training and hazard awareness

  • Emergency response procedures

  • Documentation and compliance tracking

Compliance is not a one-time setup — it requires continuous management.

What This Means in Practice

SS667 is not just a guideline — it directly impacts how your facility is designed and operated.

In practice, compliance requires:

  • Properly engineered dust collection systems

  • Control of dust accumulation in ducts and equipment

  • Integration of explosion protection where required

  • Regular system inspection and maintenance

  • Alignment with workplace safety regulations

Most importantly, systems must be designed based on your specific material, process, and risk profile.

How This Relates to Other Standards

In Singapore, SS667 works alongside:

  • MOM Workplace Safety & Health (WSH) requirements

  • NFPA standards for detailed explosion protection design

SS667 provides the local framework, while international standards often support detailed engineering design and implementation.

Common Gaps in Industrial Facilities

In many facilities, risks arise due to:

  • Dust accumulation in ducting or surfaces

  • Inadequate extraction at source

  • Lack of explosion protection systems

  • Poor system maintenance

  • Absence of formal Dust Hazard Analysis

These gaps significantly increase the likelihood of incidents and non-compliance.

How we can help

We support facilities in designing and implementing systems that align with SS667 requirements, including:

  • Dust collection system design

  • Explosion protection solutions

  • Oil mist and fume extraction systems

  • System upgrades and retrofits

  • Maintenance and performance optimisation

Not Sure What Applies to You?

If you are unsure whether your current system meets SS667 requirements, we can help assess your setup and recommend the appropriate solution.

Request a consultation