I started work back in 79 at Thames Marine who built GRP yachts & industrial mouldings. The guys who trimmed the mouldings were issued with the then new Racal Airstream helmet powered respirator, I believe they were designed for the mining & other hazardous industries. One of them showed me this bit of kit & told me what a difference it made.
In 84 I set up on my own & bought an Airstream powered respirator. At that time it cost £200, I worked in most of the local boatyards & i think i was the only bloke who owned one. At times doing a lot of GRP repairs & wood machining & sanding I virtually lived in it.
It lasted 20 years then i bought another one. 15 years later that one was getting worn out, Racal was brought out by 3M who continued making them, i bought three of them secondhand stripped & cleaned them & bought a pile of parts to keep them going. Most of the parts are still available except for motors which i cant find.
One of those GRP trimmers (who refused to wear one) died of silicosis, Several other chippies i know died of Copd & several more are now having problems.
You cant buy new lungs so investing in a good respirator makes sense!
3M, Sundstrom & Martindale are three manufacturers that spring to mind.
A quick google finds the following,
Air Fed Mask | Powered Air Respirators | Air Fed Respirator Mask ,
Make sure you are sitting down when you look at the prices!