Understanding UN TDG Foam Flammability Testing and How Dell Tech Supports Classification

Understanding UN TDG Foam Flammability Testing and How Dell Tech Supports Classification  

Foam behaviour is often one of the last things manufacturers think about when preparing aerosol products for transport. Most people are familiar with requirements like flash point, flame projection, or sustained combustibility. Yet aerosol products that dispense as a foam, mousse, gel, or paste can behave very differently when ignited, even if the liquid inside the can appears non-flammable. This is why the United Nations Transport of Dangerous Goods (UN TDG) system includes a dedicated Foam Flammability test for specific aerosol dispensers. Analysis is a key part of testing and certifying products for hazardous materials classification. 

At Dell Tech Laboratories, we routinely perform this test to support classification of a wide range of consumer, cosmetic, and industrial aerosol products. We also support certification for compliance with safety standards. The results help manufacturers determine whether their product meets the TDG and GHS criteria for an extremely flammable, flammable, or non-flammable aerosol, and which hazard class or classes of dangerous goods as defined by the UN TDG system apply. 

Foam flammability can be a critical part of the overall hazard picture, and this article explains how the test works, when it applies, and how our laboratory—one of the laboratories listed for dangerous goods analysis—helps companies navigate this requirement with confidence. Dell Tech is a recognized leader in hazardous materials testing and classification. 

The UN TDG system establishes standards recognized around the world. 

Introduction to TDG Regulations 

The Transportation of Dangerous Goods (TDG) Regulations are the cornerstone of hazardous materials safety in Canada. Overseen by Transport Canada, these regulations set out comprehensive requirements for the safe transportation of dangerous goods by road, rail, air, and marine routes. The TDG Regulations are designed to protect people, property, and the environment by minimizing the risks associated with the movement of hazardous materials, including flammable liquids, gases, and other regulated substances. 

Compliance with TDG Regulations is mandatory for anyone involved in the transportation of dangerous goods—whether you are a manufacturer, consignor, carrier, or handler. The regulations cover every aspect of the process, from proper classification and documentation to packaging, labelling, and training. By following these safety standards, companies help prevent accidents, ensure public safety, and meet the legal requirements for transportation in Canada. Understanding and adhering to the TDG Regulations is essential for maintaining compliance and supporting the safe, responsible transport of hazardous materials across all modes, including air and ground transport. 

Why Foam Flammability Matters Under the UN TDG  

The UN TDG system establishes global requirements for transporting hazardous materials, including aerosols. For aerosol dispensers, one of the key questions is how the product behaves when released from the container. Aerosols that eject their contents as a foam, mousse, gel, or paste require special consideration because the aerated structure can support and spread flame differently than the liquid inside the can. Since foam aerosols typically do not have a spray distance of 15cm or more, they are excluded from the UN TDG Ignition Distance Test (IDT) for spray aerosols, and are subject to testing under the foam flammability test instead. 

Foam aerosols often contain liquified or compressed gases, solvents, surfactants, or polymers that change the way the product burns once dispensed. A product that appears non-flammable as a liquid can become significantly more flammable once aerated. Because this behaviour can meaningfully affect hazard classification, the UN TDG includes a specific Foam Flammability test for aerosols that dispense structured foams. 

Manufacturers typically encounter this requirement during regulatory review of products such as shaving foams, hair mousses, cleansing foams, whipped cosmetics, and other formulations that dispense as a stable foam. In Canadian workplaces, it is important to understand the relevance of TDG Class 3 regulations, as certain liquids and foam aerosols may require closed cup testing and compliance with specific legal requirements and safety standards. 

There are also special cases under TDG regulations where products may be exempt from standard requirements or require additional consideration based on specific conditions outlined in the regulations. 

What Foam Flammability Testing Measures  

The Foam Flammability test evaluates the ignition and burning behaviour of foam produced from an aerosol under standardized conditions. A standardized method, such as those outlined in the UN Manual of Tests and Criteria, is used to ensure reliable and consistent results. According to the UN Manual of Tests and Criteria, the test applies specifically to aerosols that dispense: 

• foam 
• mousse
• gel
• paste 

The test determines: 

• whether the foam ignites, including the lowest temperature at which ignition occurs 
• the height of the flame 
• how long the flame lasts
• whether the foam collapses or supports further burning 

The results directly determine the aerosol’s flammability classification under GHS: 

• Extremely flammable (Category 1) if 

• • flame height is at least 20 cm for at least 2 seconds, or 
  • flame height is at least 4 cm for at least 7 seconds 

• Flammable (Category 2) if 

• • flame height is at least 4 cm for at least 2 seconds 

• Not classified as flammable (Category 3) if 

• • it does not meet the criteria above 

Foam behaviour can reveal flammability risks that are not evident from liquid-state testing such as flash point, making this test essential for proper classification. 

How Dell Tech Conducts the UN Foam Flammability Test  

Foam Flammability testing requires careful control to ensure results are valid and reproducible. At Dell Tech, our laboratory performs the test in accordance with the UN TDG Manual of Tests and Criteria using controlled conditions and experienced technicians. 

The procedure begins by dispensing the aerosol to produce a consistent foam structure. The foam is then exposed to a flame for a defined period. Our technicians record observations such as ignition behaviour, flame height, duration, and foam collapse. To ensure reliable results, the test is conducted at standing times of 30 seconds, 1 minute, 2 minutes, and 4 minutes. Each interval is tested in triplicate, using three separate cans of the aerosol product. 

To minimize operator variability, Dell Tech conducts the test under controlled environmental conditions. Temperature, humidity, ventilation, and ignition procedures are carefully maintained within appropriate ranges. All testing is performed using good laboratory practices and appropriate safety measures. 

Because this is an ignition-based test, Dell Tech reviews the product’s Safety Data Sheet before testing. SDS information helps us anticipate decomposition products and select proper protective measures for our staff. 

Interpreting the Results  

The Foam Flammability test can significantly influence a product’s classification. A foam that ignites easily or burns for several seconds may fall into Category 1 or Category 2, even if the liquid has a relatively high flash point. Conversely, foam that self-extinguishes quickly may not be classified as flammable at all. 

The following information is essential for proper classification: 

• whether an aerosol is classified as extremely flammable, flammable, or non-flammable 
• eligibility for shipping exemptions such as Limited Quantity 
• required hazard communication elements 
• transport packaging and labelling 

Dell Tech’s final reports clearly document all observations and outcomes so manufacturers can use the data confidently in their classification process. 

Products We Commonly Test for Foam Flammability  

Foam Flammability testing applies specifically to aerosol dispensers as defined under the UN TDG system. These are non-refillable metal, glass, or plastic containers containing gas under pressure, fitted with a release device that ejects the contents as a foam or similar structure. 

For example, a shaving foam packaged in an aerosol dispenser must undergo flammability testing to ensure compliance with UN regulations. 

Examples of products we commonly test include: 

• Shaving foams and gels 
• Hair mousses
• Cleansing foams and facial foaming products 
• Whipped or mousse-style cosmetic foundations 
• Foaming household cleaners in aerosol form 
• Industrial or automotive foam aerosols 

In addition to foams, Dell Tech also tests products classified as flammable solids and flammable aerosols  under UN regulations. 

Some products unexpectedly qualify for this test if their release mechanism or propellant causes the product to dispense with a mousse-like structure, even if not marketed as a foam. 

Preparing Samples for Foam Flammability Testing  

Dell Tech’s sample submission process is designed to make sending aerosol samples as smooth as possible. 

Samples must be shipped in accordance with applicable transportation requirements. Many clients use the Limited Quantity exemption when eligible, and we encourage reviewing our blogs on Limited Quantity shipments for additional guidance. There are also exemptions that apply for small quantities of dangerous goods, which may simplify shipping requirements for certain samples. Customs officials have been applying increased scrutiny to aerosol samples in recent years, particularly when the customs value is declared as one dollar or zero dollars. Using realistic values helps prevent delays. 

Each shipment should include a completed Sample Submission Form or the form may be emailed to our laboratory before the sample arrives. The form must list the product name exactly as it should appear on the final report. If the aerosol requires shaking before use, this should also be indicated so our technicians can follow the correct preparation steps. 

We also ask clients to provide the Safety Data Sheet with the sample or by email. The SDS helps ensure proper handling and safety precautions during the ignition procedure. 

Dell Tech’s quoted turnaround time begins once we have received the sample, the Sample Submission Form, the SDS as applicable, and prepayment. 

Why Manufacturers Choose Dell Tech for Foam Flammability Testing  

Manufacturers rely on Dell Tech because they need reliable, defensible data to support accurate TDG classification. Foam behaviour can be complex, but our controlled laboratory environment and trained technicians ensure consistent, objective results.  

Clients also value our ability to conduct a wide range of related TDG and flammability tests, including:  

• flash point  
• sustained combustibility
• flame projection / flashback  
• ignition distance 
• enclosed space ignition testing  

Having multiple related tests available in one place helps streamline the classification process.  

A Note for Canadian Manufacturers: CCCR, 2001 Requirements May Differ  

For companies selling foam aerosols and similar products in Canada, it is important to know that the Consumer Chemicals and Containers Regulations, 2001 (CCCR, 2001) use different criteria than the UN TDG system. Under CCCR, foams, pastes, and similar aerosol products may require flash point testing of the emitted product, and if the product can release pure propellant under certain conditions (such as when operated upright or when the nozzle is cleared), CCCR Schedule 1 flame projection/flashback testing for the propellant may also apply. For example, flammable liquids like gasoline must undergo flash point testing to ensure compliance with safety regulations due to their low flash point and volatility. 

This means that some foam aerosols, caulking products, and spray-string items may need more than one type of flammability test to ensure proper classification in Canada. 

Dell Tech performs both flash point testing and flame projection/flashback testing in our ISO 17025 accredited lab that is compliant with CCCR, 2001. 

Foam Flammability Testing as a Key Part of TDG Compliance  

Foam Flammability testing may not be the first thing manufacturers consider when evaluating aerosol hazards, but it plays a crucial role in determining the correct TDG classification. Understanding how the foam behaves under ignition ensures that the product is packaged, labelled, and transported safely and in compliance with regulatory requirements.  

Dell Tech is ready to assist with Foam Flammability testing and any other laboratory services you need to support your transport classification decisions. To request a quote or speak with our team, contact us any time. 
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