Shelter Fire Detection & Gas Monitoring

[chunt550]

Not sure if this is the correct forum, but we are installing an emissions monitoring shelter in a power plant stack, and need to provide fire detection & gas monitoring. Are there any codes that apply to the type of alarms and indication you need for this application, or for gas monitoring in general? For example, would a general horn/strobe alarm be sufficient; or would we need to distinguish between fire & gas alarms, as well as level of gas present?

Thanks