Hello,

Has anyone got any information on the types of gases and fumes produced when bituminous felt roofing membranes are burned with naked flames, both when being welded on installation, using ignited LPG type gas guns or similar and when burning in the event of a fire. Any further information on the recommended type of RPE to be used?

Am looking to update COSHH assessments to help protect our operatives who install felt membranes and for information to be included in the health and safety file for the client and emergency services in the event of a building fire.

Manufacturers seem a bit cagy, offering standard material safety data sheets that advise their standard roll product is non-hazardous, but little information about the effects of naked flames, fumes created, hazardous arising.

Any information gratefully received. Thank you in anticipaction.

As Kate says you can ask the manufacturer BUT there could be a world of difference between how the manufacturer intends the product is worked with and how your employees actually perform.

In the real world you are not trying to combust the bitumen which will give rise to the greatest number of nasties but soften it enough so it flows to form a water resisting membrane on completion of the task.

Your question (which is why manufacturers would be as you describe it "cagey") is dependent on a lot of variables - temperature, oxygen availability, IF the substances react fully or partially during burning, adjacent materials, the constituents of any substrates or impregnated membranes.

Dwelling on your question I can't recall ever seeing roadworkers or roofing installers wearing any form of RPE whilst working with bituminous products.

HSG 33 mentions the use of masks to control chemicals but I suspect most employers deem natural ventilation with outdoor works adequate

I suspect you may already be a member of the National Federation of Roofing Contractors

https://www.nfrc.co.uk/knowledge-hub/NFRC-publications

Then there are the manufacturer bodies who can also provide guidance:

asphalt roofing manufacturers association https://www.asphaltroofing.org/

Roof Coating Manufacturers Association https://www.roofcoatings.org/

Mastic Asphalt Council https://masticasphaltcouncil.co.uk/

Hi Beever

Those doing e.g. Built Up Roofing shouldn't be burning the asphalt (not least as they don't want to start a fire), but rather heating is as Roundtuit indicates to enable it to flow reasonably freely.

In ye olden days the roads were built with coal tar, identified as a known carcinogen and some roads in the UK may still have tar in them.

Bitumen is much less toxic, though a suspected carcinogen, but in a typical open air roofing (or roadworking) environment levels of "off-gasing" should be relatively low.

Roofer Fact Sheet (wabbajack.co.uk)

Very much on board with "torch-on" hence mentioning the suppporting substrate being combusted.

In the old days it was true roofing "felt" that was manufactured which involved many forms of recycled fibres wool, cotton, nylon, rayon, polyester etc. hence the supplier being unable to describe the combustion gasses of a fixed content.

they are all a bit cagey as it is and industry issue similar to welding fumes...so denial rather than fix...

NIOSH ahve some useful guidance...and there are other medical studies.

Among the compounds identified in bitumen and its emissions, some have been listed as carcinogenic by the International Agency for Research on Cancer (IARC) and/or listed as carcinogenic, mutagenic, toxic to reproduction (CMR) and/or hazardous by the European Union. The IARC recently identified exposure to oxidised bitumen and its emissions during waterproofing procedures as probably carcinogenic to humans and exposure to bitumen and its emissions during the application of bituminous asphalt concrete and/or during paving work as possibly carcinogenic. 

There is no defined guidance on it however, in the US OSHA's quantitative risk assessment estimated a significant risk of lung cancer among exposed workers at levels as low as 0.2 mg/m3. The American Conference of Governmental Industrial Hygienists (ACGIH) currently recommends a Threshold Limit Value (TLV) of 0.5 mg/m3 as an 8-hour time weighted average. NIOSH currently recommends no more than 5 mg/m3 for a maximum exposure.