Mineral Oil

[GB]

Does mineral oil constitute a flammable liquids in accordance with the COMAH Regs Schedule P5b?

[AnthonyB]

Comparing the details on a mineral oil MSDS and the criteria in that section I would say not

[GB]

Thanks Anthony,

Here are my thoughts, however random they may be, a flammable liquid to my understanding needs to have a flashpoint of less than 100C with most data sheets that I see stating mineral oil with a flash point of 145C which makes in a combustible oil rather than a flammable liquid - would you agree or disagree?

I have seen an NFPA document stating a flash point of 93C and classifying as a Class 3 which mixes it up a little.

The use of the oil however where temperatures are elevated, pressurised with high operating voltages in close proximity - does that take it into the territory of a 5b Flammable Liquid under Schedule 1 of COMAH taking into account Note 12 of Schedule 1 and that I have over 300 tonnes of it sitting inside operation sub station transformers?

[jayjay]

Have a look at HSG 140 this document may answer your question

http://www.hse.gov.uk/pUbns/priced/hsg140.pdf

[John Webb]

Is there any possibility of refilling the transformer(s) with a modern cooling fluid which is not carbon-based? I understand there have been considerable developments in this area in recent years.

[GB]

We have tried to persuade the client to switch to ester based cooling fluids which would remove the fire hazard. We felt this possible as the transformers are not yet built therefore its not a change of oil, its a change in the specification.

The client has thus far refused the change citing simply providing copious amounts of water for fire fighters for the site (despite it being very remote)

Looking at HSG 140, there is class of flammable liquid where the flashpoint is above 60C and the liquid used at a higher ambient temperature.

[kurnal]

This may not help very much GB but have you shown the client videos of substation fires? There are a number available online. Showing videos and talking about consequential losses has been as useful tactic for me in the past.

[GB]

To close this thread off - I have copied the response from HSE for information for anyone interested.

You reference note 12 of Schedule 1 of the Regulations which refers to paragraph 2.6.4.5 of the CLP Regulation regarding the classification of flammable liquids.  This paragraph reads, ?Liquids with a flash point of more than 35?C and not more than 60?C need not be classified in Category 3 if negative results have been obtained in the sustained combustibility test L.2, Part III, section 32 of the UN RTDG, Manual of Tests and Criteria.?,  Note 12 to Schedule 1 of COMAH references this then notes that ?This is however not valid under elevated conditions such as high temperature or pressure, and therefore such liquids (my emphasis) are included in this entry (my emphasis).  As this entry (Schedule 1, Part 1, P5b) and such liquids (those described in para 2.6.4.5 of CLP) refers to liquids with a flash point no greater than 60 ? C this would not apply to a liquid with a flash point of 145? C regardless of the processing conditions.

Liquids not covered by the Flammable Liquid categories P5a or P5b in Schedule 1 of COMAH can still come into scope under P5c with tonnages of 5,000 and 50,000 if they are otherwise classified as Flammable Liquids Categories 2 or 3.  If you think there is a possibility this substance could be classified as flammable then you should review the relevant sections of the CLP Regulation and guidance, there is a decision logic diagram for flammable liquids at Figure 2.6.4 on page 145 of the CLP Guidance and the section regarding the classification of flammable liquids in CLP is 2.6 from page 93.  I would note that as a general rule substances with a flash point in excess of 60?C are not classified as flammable.

Many thanks for all of your posts and comments.