Based on what remains in other gas protected buildings on the Fort, the air filter installed between these two fittings would have been hot swappable. Just shut off the blower, close a couple of valves and unbolt it. The filters are about the size of a 55 gallon drum and would have been mounted near floor level. Alll 3 filters are in the HECP and the original 2 are in the Mortar Battery Plotting room, plus we have one that we'll be setting up for a display in the Coast Artillery Museum. There would have been an inline blower and based on the way that two of the other gas protected buildings are set up, it would have been before the filter so that it would still move air when the filter was bypassed. The HECP has a different layout for the air system because of it's size.

Photo album created with Web Album Generator