Gas Mask Filters
If you like the resistance a filter adds to breathing with a gas mask, you can add your filter to the end of your hose.
When you do add a filter, you may find that you receive a small amount of aromas when you are not pumping. This is inevitable and is because the resistance of the filter makes it possible to pull a small amount of air and vapour through the bulb and the poppers bottle when you breathe in.
Filters Safety Note – Do not use any filter made before 1990. Civilian respirators contain chrysotile (white asbestos) and filters made for the military contain crocidolite (blue asbestos), both types of asbestos are carcinogens. You should treat any military surplus filter as a serious health hazard.
As happens with the additional load on your breathing that a gas mask filter adds, the increased resistance presented by the liquid in a bubble or ‘bubbler’ bottle, may also cause a small flow of air and vapour to be pulled through the pump bulb and attached poppers bottle each time you breath in.
If this is found to present a problem, the air inlet tube in the bubble bottle should be withdrawn slightly so it is not as deeply submerged in the liquid. This will still allow the bubble bottle to add breathing resistance and possibly its own aroma to the air you breath, depending on the liquid you choose to put in the bubble bottle.
When you connect a pump hose to your bubble bottle setup, you must remember that the aromas bottle wants to be roughly upright, unless you are using cotton wool in the aromas bottle.
You should never ever use a rebreather bag when you are alone. Whenever a rebreather bag is used, it is essential that a good supply of fresh air is instantly available.
If you are adding an aromas pump hose to your rebreather setup, you can connect it to the mask with the bag and any valve assembly attached to the free end of your pump hose.
Twin Inlet Masks
Some gas masks and heavy rubber masks have two inlets. Twin inlet gas masks are intended to offer the choice of which side the hose or filter may be attached, a speech diaphragm is normally used in the side without the filter. It is possible however, in some instances, to add a standard gas mask hose to each side for visual effect. In this case, a T connector is used to join the hoses together and to connect the pump hose and any additional items.
Heavy rubber masks and multifunction masks with twin inlets, normally include appropriate twin hoses with a removable connector or permanently joined hoses which have a single 40mm female connector as part of the junction where they meet.
In all cases the pump hose is connected to the single inlet.
In all instances where there are additional hoses between the aromas pump hose and the mask, it will take longer for aromas to reach the user when pumping. Because of this, there is a tendency to pump more aromas into the tubing than normal and a first breath in may not contain all the vapour in the tubes.
The pump hose is usually connected directly to the mask but if the wearer will be lying down for long periods, it may be an advantage to insert a standard hose between the aromas pump hose and the mask. This can make it much easier to keep the aromas bottle upright. If you are including a standard hose, it may be useful to add a 1.5 metre Pump Bulb Extension Kit to make the pump bulb more accessible.