Even though people like to joke with careless expressions such as "When instant count, the police are merely moments off", there is a truth to it in circumstances of the fire, biohazard incidents, chemical spills, or an unintentional release of noxious gases.
After the alarm goes off sounding that an injury has happened in your area or smoke begins to get into your workspace, then there may not be time for you to access an Emergency PPE Equipment Station. Worse still, the emergency may already be between you, the channel, and the only real exit from this construction.
When that happens, the best, immediate protection you have will function as the Personal Escape Mask which can be carried around your neck, in a purse, or stored in a table. You can get to know about an effective face mask in the UK via https://www.u-mask.eu/mouth-masks.
Ideally, it will need to fulfill up with the OSHA standards for Air Purifying Escape Respirators (APERs) and become light enough to comfortably wear in what is likely to be considered a hostile environment as you are trying to protect your life.
APERs standards were developed to guarantee a set of requirements all manufacturers check out and that buyers from corporations to individuals could readily comprehend. Among the criteria which APERs had to meet were a field of view, immunity to fogging, compound permeation, functional design, ease of donning, and shelf life.
This became especially important following the 9/11 strikes when private organizations began searching for protective gear to their employees that may be readily and safely used with little to no training.