Posted By Syrup You are quite right, CoSHH is not your strong point. If your main concern is fire safety/reactivity, then this has nothing to do with COSHH - Control of Substances Hazardous to Health. You should get familiar with DSEAR - Dangerous Substances and Explosive Atmospheres Regulation The clue as to what risks the regulations are meant to address, are in the titles..... You should cross releate your DSEAR assessments with your fire safety assessment as per the RRO requirements. Either Google for a reaction/segregation matrix or there is one in the HSE guidance to warehousing and storage of chemicals. Forgotten the specific reference/title.

Posted By garyh I believe that you should look in HSG71 CHEMICAL WAREHOUSING the storage of packaged dangerous substances Table 1 on page 24 shows exactly what class of materials can and can't be stored together. There is a matrix showing the symbols of the hazards classes and what you need to do. In an nutshell, you can't lump "chemicals" together in one location unless the hazard (classification) is the same, eg no flammable with toxic, no flammable with corrosive and so on. It is actually straightforward, and you don't need to know about DSEAR or COSHH as such. However, you should have access to the advice of someone knowledgable in this area. Job done!