Improving Fire Performance of Plastics Products
Every year there are around 40,000 UK house fires that cause around 300 deaths and 9,000 injuries. Plastic products are usually blamed for the contribution to fires as the chemicals used within them catch alight easily.
Plastic products are sent out to be tested to see if the product extinguishes itself or spreads within the fire. Plastic products are sent out to test if they are resistant to setting alight from the start.
Burn Tests:
There are two types of burn tests on plastic products.
The first being a V- rating, which is a vertical burn test that tends to be more stringent and high rated. If the product fails, the second test is then to execute the ‘HB’ (horizontal burn) where the plastic product is laid at 45 degrees and then tested, it then will attract a lower rating.
Safety Standards
The UL49 safety standard is assigned to testing the flammability of plastic products, which is followed by the testers result, it will either pass or fail the HB rating after being tested to this standard.
V-Ratings
Performer’s show 3 levels of V ratings. Starting with V-0 which is the best rating, V-1 which is medium and V-2 which is a low rating. If the product fails the test, it will then be tested for a HB rating.
How are these tests executed?
Procedure for V-Ratings
- Testers use around 10 test pieces that are plastic products (5 sets of 2) per thickness
- Half of the products are left to sit at 23 degrees for 2 days
- The other half of the plastic products are left to sit at 70 degrees for a week
- These test pieces are held vertically, 10mm above a Bunsen Burner
- A 20mm blue flame is then applied to the sample and removes after 10 seconds
- If the plastic product stops burning within 30 seconds, the flame is re allied for another 10 seconds
- If there happen to be any drips, these are able to land on cloth material
For Plastics Products to pass for V-0 Ratings
- The product mustn’t burn for more than 10 seconds after flame applications
- The joint burning time isn’t allowed to exceed 50 seconds for the whole batch
- It cannot flame all the way to the top of the sample of the plastic products
- There cannot be any flaming drips that set the material cloth below alight
- The flame cannot glow for more than 30 second after the 2nd flame application
For Plastic Products to pass for V-1 Ratings
- The product mustn’t burn for more than 30 seconds after either flame application
- The joint burning time isn’t allowed to exceed 250 seconds for the whole batch
- It cannot flame all the way to the top of the sample of the plastic products
- There cannot be any flaming drips that set the material cloth below alight
- The flame cannot flow for more than 60 seconds after the 2nd flame application
For Plastic Products to pass for V-2 Ratings
- The product mustn’t burn for more than 30 seconds after either flame application
- The joint burning time isn’t allowed to exceed 250 seconds for the whole batch
- It cannot flame all the way to the top of the sample of the plastic products
- There cannot be any flaming drips that set the material cloth below alight
- The flame cannot flow for more than 60 seconds after the 2nd flame application
Procedure for HB Ratings
The samples are left to sit at 23 degrees for 2 days and are mounted at a 45-degree angle. The sample is then marked at 25mm and 100mm from one end; it’s then held at the top end and the bottom end is 10mm above wire gauze.
A 20mm blue flame is then applied to the plastic products and then removed after 30 seconds.
If the burn continues after the flame is removed, the time that it takes for the plastic products to burn between the two marks is measured and then is calculated and recorded per minute.
For Plastic Products to Pass HB Ratings
- The plastic mustn’t exceed 40mm per minute over a 75mm span (samples 3mm and thicker)
- The plastic mustn’t exceed 75mm per minute over a 75mm span (samples of less than 3mm)
- The plastic must stop burning before it reaches the 100mm mark
Added: 18 Oct 2017 08:59
Back to News