Fire Safety

Fire properties of materials are a key aspect of fire protection at CERN.
Experiments and facilities are workplaces with human life to be protected, and fires may have radiological and environmental impacts also outside CERN perimeter.

Fires are very often capable of considerable damage already with minimal quantities of mass involved in the combustion process.

The risk is strongly correlated with the attitude of materials to ignite and propagate, and to the toxicity and acidity of the by-products released with smoke.

All activities and facilities at CERN, where polymers may be used, undergo a logic of avoidance of hazardous classes of materials, substitution with non-dangerous ones, and minimisation of the residual risk via mitigation measures.

CERN enforces this approach via its safety regulation, which is binding for all entities working or utilising CERN facilities.

It is of worth mentioning that difference exist between regulation of different countries, so materials have to be checked with respect to the specific regulation enforced by the competent Safety Authority (in this case, CERN regulation).

Central pieces of the safety regulation applicable at CERN on this matter are the CERN Fire Code E, containing general provisions, and specifically for materials, the Instruction safety 41 and SSI-FS-2-1 (Cables).

The key aspects are:

1) materials shall have low or minimal attitude to ignite and propagate. Specific classes of acceptance are given.

2) toxicity and acidity of smoke shall be minimal. This excludes (or reduce to near zero) the presence of the Halogens Elements of the Periodic Table (Cl, F, Br, I), Sulphur and Phosphorus in the composition of the materials. Specific tests are necessary when information on this aspect is not available.

3) Opacity of the smoke in specific tests shall not be larger than a given value

4) Acidity of the smoke shall remain above a given threshold, when measured in a specific test.

All these aspects, and the tests required, are fully described in the document 

https://edms.cern.ch/file/335806/LAST_RELEASED/IS41_E.pdf
https://edms.cern.ch/file/2669584/LAST_RELEASED/SSI-FS-2-1_EN.pdf

In the same document, for convenience of the reader, a classification of the most common materials (accepted, accepted with limitations, not accepted) is also given, basing on a classification work conducted internally using the four criteria described, on materials used for different applications.

As experiments and their ancillary equipment typically are developed basing on specific material properties, changes for CERN-compliant materials at a later stage are often impossible.

This basically obliges to enforce safety renouncing to the possibility of avoiding or substituting the danger, leaving as sole tool in the hand of safety the protection via compensatory measures, defined through derogations, that should be left to limited cases where all the alternatives have been properly explored at the right time.

For this reason, it is of worth mentioning that CERN specific requirements should be understood and factored in since the start of the development of any experiment or piece of equipment that may have to be used at CERN.

This can indeed be a specific risk in the project-management sense of the term, not only for CERN but and for the collaborating Institutions and should probably be addressed with the most opportune forms of communication.