The reaction of products in the event of a fire is critical when it comes to effective product specification. There are recognised national and international standards related to products performance and reaction to fire. Flexicon can offer a wide range of conduit systems which have been independently tested.
Low Fire Hazard systems are required to protect the public, personnel and property in the event of a fire and are demanded by specifiers, Industry Bodies, Train and Network Operators, fire services and even insurers.
At Flexicon we define a Low Fire Hazard product by having all of the following properties:
- Highly Flame Retardant: to prevent a fire starting 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 an indication of low smoke and low toxicity. It also rules out halogen acid gas emission – a fact that is of interest to insurers as acid smoke can destroy computer equipment and damage the structure of a building. Halogens are Fluorine, Chlorine, Bromine and Iodine.
Our product development programme involves extensive testing to the latest Rail Industry standards to ensure the safety of our products, thus providing confidence for specifiers and consultants when it comes to their reaction to fire.
EN 45545 – European Fire Safety
This new European standard is rapidly replacing national standards in Europe and consists of 7 parts.
Conduit performance is quoted to EN 45545-2. R22 is for interior parts and R23 is for exterior parts.
There are three defined levels of performance related to the reaction of fire, HL1, HL2 and HL3. HL3 is the highest level of performance when it comes to the reaction to fire, and will be specified for higher risk applications.
This UK standard relates to passenger rolling stock and are classified into two main categories depending on the operating environment.
Category I relates to Underground applications, which is then sub divided into 2 parts, depending on operating conditions.
Category II relates to Surface stock.
TFL S1085 – Transport for London
This standard is used by London Underground to control the materials used throughout their Underground and Crossrail System.
This standard considers flammability, smoke and toxic fume emissions and includes tests from BS 6853.
Products approved for use have APR numbers. Flexicon’s range of conduit systems have 6 Certificates, covering 11 products as Authorised for use.
Certificate No. 296, conduit types FU, SSU and FUSSB.
Certificate No. 297, conduit types LFHU, LFHUBRD & LFHP.
Certificate No. 298, conduit types FPR and FPRSS.
Certificate No. 658, conduit type LTBRDLFH.
Certificate No. 2020, conduit type LTPLFH.
Certificate No. 2624, EXD barrier glands.
NFPA 130 – North American Standard
This standard is used by US Rail authorities.
Tests called up by NFPA 130 are ASTM E 162 (for flammability) and ASTM E 662 (for smoke). Other North American standards are: ASTM E 1354 Heat Load, Boeing BSS 7239 Toxicity
NF F 16-101/2
This French rail standard consists of an Ignition rating (I) and a Fume Rating (F).
The lower the number the higher the level of performance when it comes to the reaction to fire. I2 F2 offers more protection than I3 F2.
This German standard consists of three elements including Flame Spread, Smoke evolution and Flaming droplets.
Products categorisation looks like this: S4 / SR2 / ST2.
AS/NZS 1530.3 – Australian Standard
This standard is used by Australian Rail.
CEI 11170 – Italian Standard
This standard is used by the Italian Rail. Products categorisation looks like this: LR4.
Russian Fire Safety Certificate – 1374363
Methods of Assessing Fire Performance
The minimum requirement is self-extinguishing according to the worldwide conduit system standard BS EN IEC 61386 where a vertical sample of conduit is exposed to a 1kW burner and must extinguish within 30 seconds of the removal of the flame. The char must not have travelled more than a certain distance up the sample and there must be no flaming droplets. Fittings are tested by means of a 750°C glow wire test.
To assess how flame retardant a material is, the normal test method is to measure the Limiting Oxygen Index (LOI) according to BS EN ISO 4589-2 which determines the percentage of oxygen that needs to be present to support combustion. The higher the LOI percentage, the greater the flame retardancy of the material. Oxygen present in normal air is approx. 21%.
Another method is the glow wire test, BS EN IEC 60695-2, which applies a glow wire to a plaque of material at 750°C, 850°C or 960°C.
UL94 is an Underwriters Laboratories standard that measures the rate of burning up a vertical test plaque, category V0 is the most flame retardant followed by V1 and V2. There is a category HB but this indicates that the material is flammable even along a horizontal test plaque.
Low Smoke Emission
There are a number of fire tests, mainly from the rail industry, where a specified sample of material is burnt under controlled conditions in a given size smoke chamber and the smoke obscuration of a defined beam of light is measured. Although the different tests are similar, the results and the requirements are different.
There are a number of fire tests, mainly from the rail industry, where a specified sample of material is burnt under controlled conditions in a given size smoke chamber and the fumes are analysed for various gases, the concentration of each gas is then multiplied by its toxic potency to give a toxicity index.
Although the different tests are similar, the results and the requirements are different.
If halogens, sulphur or phosphorus are present in a material, it is unlikely to pass the low toxicity tests.
The Halogens are fluorine, chlorine, bromine and iodine. Chlorine is the most common in PVC, fluorine is in fluoro-polymers and bromine appears in flame retardants. All of them give off highly toxic fumes and thick smoke. A material cannot be considered as Low Fire Hazard if it contains halogen. However a halogen free material is not necessarily Low Fire hazard as it may not be low toxicity, low smoke and highly flame retardant.
Halogen content is assessed by various chemical tests and analytical techniques.
Classification of Low Fire Hazard performance (LFH)
Inherently Low Fire Hazard
These products are made entirely from metals so there is no non-metallic material to burn or create smoke or toxic fumes.
Inherently Low Fire Hazard products include; FU, SSU, FB, FUSSB, FTCB, FSS, FSSBRD and metal fittings.
Extra Low Fire Hazard
These products have a Limiting Oxygen Index of greater than 32% as well as being low smoke and low toxicity.
Extra Low Fire Hazard products include; LFHU, LFHUBRD, LTPLFH, LTBRDLFH, LFHP, FPR, FPRSS, FPIHR, FPIHRSS and FPRTC.
Standard Low Fire Hazard
These products have a Limiting Oxygen Index of greater than 26% as well as being low smoke and low toxicity.
Standard Low Fire Hazard products include; FPAS, FPAH, FPI, FPISS, FPIH, FPIHSS and PA66 fittings.