Depends on the job, project, scale, etc. Typically just follow OSHA type rules but also a lot don’t. I frequently see roofers running around on roofs with no fall protection as an example. These jobs are usually done by the time an inspector would drop by. We barely have enough inspectors to keep up with the required trade work inspections. But If there’s something like a hard hat requirement or high visibility vest is required then it’s typically monitored closely and can cause major issues. These tend to be large civil or commercial projects. I do single family residential so it’s generally not applicable and no random safety inspections occur. The random stuff we get is usually the city code compliance. In the context of Phase Change Materials, I’m not aware of anything close to a mandatory PPE requirement on something like that. I don’t think many people in the trades are even aware this exists, or don’t wan the extra weight or most likely the cost associated. Some of these guys barely invest in decent tools for the trade they specialize in.

Until it becomes mandatory I doubt anything would change. The machismo factor is such that anyone that can’t deal with the heat isn’t fit for the job. They’d probably get kicked off the crew quickly. I don’t employ anyone just strictly subcontract so it’s not in my interest to force them to exceed whatever their normal PPE requirements are.