One the biggest and totally preventable dangers associated with gas-fired heaters is carbon monoxide poisoning. It’s a risk that is mitigated with knowledge of how to properly install and ventilate gas heaters. According to the Centers for Disease Control, about 20,000 people go to the emergency room and nearly 500 U.S. deaths occur every year from carbon monoxide poisoning.

Heater clearances are set by the National Fuel Gas Code and apply for all gas heater models. The following are a set of general guidelines for outdoor installations: Overhangs (roofs, ceilings) must be 3 feet higher than the top of the heater, depending on manufacturer specifications.

The heater must be open on three sides.

Doors and windows must be 4 feet to the side or 5 feet above the heater. The top of the heater must be at least 3 feet above forced air inlets located within 10 feet of the heater.

The heater must be at least 5 feet from the pool wall unless separated by a permanent barrier.

Indoor heaters must be certified by American Gas Association for indoor use withanapproveddrafthood.Indoorheaters must always be vented to the outdoors.

Vent piping the same size or larger than the draft hood outlet is recommended.

Vent pipe must be capped to protect against rain or snow.

The discharge opening must be at least 3 feet vertically from the roof surface and at least 2 feet higher than any part of the building within 10 feet.

The vent stack should be at least 5 feet vertical height above the draft hood outlet. The vent cap location should have a minimum clearance of 4 feet horizontally, unless a 4-foot horizontal distance is maintained from electric and gas meters regulators and relief equipment.

The weight of the vent stack should not rest on the draft hood.

The heater top and draft hood must be readily removable for maintenance and inspection.