Low Fire Hazard (LFH) conduit systems are becoming an increasing part of the specifications in many applications.

Low Fire Hazard systems are required to protect personnel and property in the event of a fire and may be demanded by specifiers, occupiers, fire services or even insurers. Flexicon nylon conduit systems define a Low Fire Hazard product as having all of the following properties:

• Highly Flame Retardant to prevent a fire or limit its' development if one does start.
• Low Smoke emission in the event of a fire to enable personnel to see their way to escape.
• Low Toxicity in the event of a fire to ensure personnel are not overcome during their escape.
• Halogen Free gives and indication of low smoke and low toxicity. It also rules out halogen acid gas emission. This is a fact of interest to insurers as acid smoke can destroy computer equipment and damage the structure of a building.

Test Used

• Flame Retardancy UL 94 is an Underwriter Laboratories standard with flammability classifications HB, V-2, V-1, V-0. A V-2 rating indicates that a product is self-extinguishing, and V-0 is highly flame retardant. Most Flexicon Nylon Conduit system products have a V-2 rating or better.
• Smoke Density is evaluated to BS6853 annex D.8.3, Code of practice for fire precautions in the design and construction of passenger carry trains. A plaque of materials is burnt in a 3 meter cubic chamber. A graph of smoke opacity against time is plotted which shows the maximum opacity (Ao) and the time taken to reach that opacity. LFH material should have Ao<0.03
• Toxic Fumes British Naval standard NES713 burns a set amount of material and analyzes the gases given off. The volume of each gas is multiplied by the toxicity index for each gas. The toxicity index for each gas is added together to give an overall toxicity index for the material. LFH material should have a toxicity index maximum of 10.