I have just completed my first Fire Rated Room which has been approved by
both the Superior Fire Department and the Superior Building Inspector’s Office.
Following are the requirements as I understand them. In the City of Superior they should get your room approved in most cases, but may or may not in other Cities. If you have done something different, found a less expensive way. or a cheaper product; call
or e-mail me and I will post it here. As a contractor in town, I would be willing to stop by and look at your project at no charge to make suggestions. If you would like one built, I will give you a price and complete the project.
1. Combustion air
All combustion air has to come from outside of the building.
A vent from the Fire Rated Room into the basement is not acceptable.
You need to have at least one square inch per 3000 BTU/hr of the total input for of all equipment located in the enclosure, I have provided the math, calculations, and examples below. But never less than the sum of the areas of all vent connectors in the confined space. This means if you have 6” vent from your boiler and a 3” vent from your hot water heater you will also need a minimum of 9” of combustion air. The incoming pipe can never be smaller than the total out going. The combustion air vent is required to be 12 inches or less from the ceiling. MAKE SURE YOU USE INPUT NOT OUTPUT SPECIFICATIONS FROM MANUAL OR LISTED ON EQUIPMENT.
Example #1 150,000 btu/hr input gas furnace
150,000 divided by 3,000 = 50 square inches
An 8” pipe is perfect for this example but you could also substitute two 6” pipes
Example #2 Multiple units
175,000 btu/hr input gas boiler and two 40,000 btu/hr input gas hot water heaters
175,000 + 40,000 + 40,000 =255,000
255,000 divided by 3,000 = 85 square inches
A 10” pipe and 3” pipe or two 8” pipes or three 6” pipes (see measurements below)
ANY SIZE COMBINATION IS OKAY IF IT HAS PROPER SQUARE INCHES
You can use square, rectangular or round pipe but keep in mind you will need some kind of
undampered vent with a screen for birds and bugs on the outside of the building.
Round pipe is readily available with the undampered vents
Square inches in round pipe (Common sizes)
• 3” diameter = 7.06 square inches
• 4” diameter = 12.56 square inches
• 5” diameter = 19.63 square inches
• 6” diameter = 28.27 square inches
• 8” diameter = 50.26 square inches
• 10” diameter = 78.53 square inches
• Larger vents are harder to find but plumbing and heating companies will be
able to supply them for you.
2. Clearance from combustibles for vents
ALWAYS CHECK FOR MANUFACTURES LISTED CLEARANCE
Here are some general guidelines for pipes up to 8”, if larger call Building Inspection Office.
Single wall metal pipe 6” minimum
Listed type B gas vent 1” minimum
If your type B vent has to pass thru the fire rated wall you cannot sheetrock up to it and mud it in you have to use a wall thimble and keep the minimum clearance.
There are many different combinations in this area. But these appear to be the general rules.Again, if you have any doubt at all call Building inspection
3. Clearance from combustibles for water heaters, furnaces and boilers
This will vary from one piece of equipment to the next in most cases they will be written on the equipment somewhere I found them on both of mine. Please take the time to thoroughly look for this information Building inspection will require it. As a general rule 1” from sides and back and 6” from front but you also have to allow a service area directly in front of all equipment that appears to be 3 foot.
If possible allow for more
4. Fire rated doors
The requirement is for a one (1) hour rated door and frame. I am recommending here that you purchase one. When you go to order your door you will find that a one (1) hour door is available but at a premium. You will want to order a 90 minute door. You will need both the door and extension kit. Menards has the best price I could find at $251.
The door I received had an “L” frame you can install and trim, or just mud and tape it.
If possible get the door before you frame up the room. I did not. The rough opening size that Menards gave me was about an inch to large for the door resulting in time-consuming adjustments.
If you are building from scratch, the cost for 5/8 sheetrock is your best deal. But you may already have something else on your walls or ceilings which is acceptable i.e. utilizing concrete basement wall. There are about 20 pages of tested one hour rated materials which can be found in the Building Codes. Most materials will have some time rating by the hour. If you are building your room from scratch; install sheetrock on the ceiling first. If you have pipes and other obstacles in the way you may be able to get the larger pieces up without your walls in the way. Build it a little larger than you plan on making the room so as to extend beyond the planned walls. The sheetrock must extend over the top of the walls so the walls can be taped up to the ceiling on both sides of your wall. Other wise you will have to sheetrock in between the joists up to the floor, then tape all cracks. When building the walls, both sides need to be sheet rocked and taped to get the one hour rating. No holes, cracks, or openings of any kind are allowed in the sheetrock. No windows are allowed unless they are fire rated glass.
The Fire Department is still letting a lot of stuff thru but if you are building a new room
and like to do things once, this is the correct answer.
Fire Department # (715) 394-0227 Get it in writing
City Building Inspection # (715) 395-7288 Ask for Dan Curran
If you find any of this helpful, good, you may with my permission. You will find some advise, opinions, instructions and statements which are intended for your information. I do not guarantee the accuracy or completeness of any of it. I may refer to vendors but they are parties I have no control over. The prices I cite may or may not be or remain wholly accurate, the product may not be available it is up to you to check it out yourself. There are ordinances and laws which govern this construction. You are responsible for determining what they are and compliance. I am assuming you are intending to follow with all such
laws, restrictions, and/or regulations. You should NOT rely solely upon this information or my opinions and you should consult with someone licensed or certified for the appropriate task before you start. This is not intended to be a substitute for a consultation with an expert because the applicable rules, laws, standards may differ substantially in individual situations or in different states, counties, or cities. Ultimately you are solely responsible for any construction decisions or actions you take or omissions you commit.