The old Mines Rescue Service might be able to provide some information see https://www.mrsl.co.uk/t...ning/breathing-apparatus

Simon, in my opinion you should contact your local fire and rescue service to come in and see what you have and for them to recommend and assist with your rescue procedures. Whatever your procedure and equipment if your rescue fails it is they who would come to your rescue. These days fire appliances are few and far between and you will need to call them first if an emergency situation arises. Whether you need them or not it is good to have them on their way to you. Full protection suites are great but they take time to don and every one needs assistance with dressing, zips etc. there should be two rescuers dressed the same in case one rescuer has difficulties and need help. You should also have two Emergency people outside, dressed the same in case the first two struggle and need help. Further what about De-contamination? This is needed because the suits will be contaminated by whatever the chemical. The De-con team will also need to be suited and all equipment sealed up in double bagging and disposed of or sent for cleaning. You may say I am overplaying this, you are free to do so, but I was in the fire brigade and on the Emergency Tender which carried such equipment, and experienced the use of those suits at chemical incidents and was in charge of the De-contamination Unit at times.