I work at a manufacturing facility. We have several gas fired kilns for ceramic products. We have a total of five tunnel kilns that run 24/7, and four periodic kilns that run pretty much back to back. Once loaded, its fired, cooled, emptied and reloaded to start all over again. Several of these kiln pull combustion.make-up air from inside the building. There are a few outdoor air louvers, but no where near enough, given the net free areas, and cfm they can deliver. So NFPA 86 states you must provide proper amount of combustion/make-up air to allow proper operation of the gas fired equipment. So I have raised the issue to our safety department and their response is that we are providing the combustion/make-up air from inside the building. Naturally they do not want to spend the money to correct the issue the right way. One of our periodic bell kilns just underwent a combustion upgrade. It is located inside a room by itself. It has one outdoor air louver. The kiln exhaust 10,380 cfm, the outdoor air louver delivers 5430 cfm according to the manufacture after factoring the net free area. Thus a room vacuum occurs. To make this worse there is one 21,000 cfm roof top mounted exhaust fan in this same room. So this makes the problem worse. I raised the issue stating that we have to address the room vacuum as part of the kiln upgrade. Everyone ignored me. So after getting tired of me hounding them about the issue, the company performing the kiln combustion upgrade was contacted. They stated their responsibility was for the kiln only, that the building was our issue. I need the NFPA standard (specifically) that addresses my issue. I know that mechanical louvers must be interlocked, and intake fans specific to combustion/make-up air also need interlocking with operation. Since my company is not wanting to spend any money on this I need to have the NFPA standards and codes to force this issue. Also I am thinking that if a mechanical louver or make up fan is running pushing air into a building for use at a gas burning device. I would think that in the event of a building fire, you would want that fan shut down, and air louvers closed. To stop feeding air to a fire. Am I way off base here? I need lots of help on this. Thanks!