Chile Forum

OK fellow engineers - new discussion.

I have built a separate,firewalled (internit and steel) sala de caldera for the boiler and termo. I am not disputing the need for a makeup/combustion air intake.

In the civilised countries, we generally use a single makeup air vent sized to the necessary rate of combustion of the burners inside the room. That makeup air is usually specified to be at a low point in the room and in some cases directly feeds the inlet air for the burner. Did I say a single inlet for a room of about 2,5 x 2,5 metres?

Well, here the rep for the gas company says there has to be makeup air venting top and bottom in the door. The door? The door is the only combustible part of walls and ceiling. Combustible door is permitted by SEC. Putting vents in a wooden door only assures that any fire that gets started will burn through that door much more quickly if it is the location of the makeup air venting.

Venting top AND bottom? No sense to me. A single vent, low mounted, of adequate sizing, should be adequate and meet SEC intent. That allows some desired heat to be retained in the room. I smell chamullo, a practice of we-always-done-it-this-way. Comments from those with SEC/persona autorizada experience?

Just leave the door off...that way if there IS a fire, you´ll be able to see it!

El pescado wrote:Just leave the door off...that way if there IS a fire, you´ll be able to see it!

Another helpful hint from Customer Service.

xxx

I'm inclined to agree with El P on this one, in most installations there is a mandate for high and low combustion air, probably to assist convection.
The plinth for HW heaters and FAUs is standard for garages here in the US for the reasons stated but inside a house it's for makeup air.
I brought a few of these for my califont closet.
http://www.midgetlouver.com/products/special.htm
I drilled holes to the outside wall, inserting plastic pipe from Volcanit to exterior siding, terminating with the caps shown. The 2" ones are a snug fit inside the 2" ABS drain pipes available in chile and once painted to match the siding they look good. For your needs you might need to go larger but that might help you avoid cutting the door.

As it turns out I was able to get acceptable makeup/combustion air without cutting the door. Vent went into the internit above the door, and additional holes in the floor of the elevated sala de caldera structure.

Regarding discussion of gas leak, kerosene and so forth --- SEC guy says the venting is not for dilution of gas leaks, only for combustion air makeup, and any storage of other combustibles such as kerosene in that dedicated caldera room is prohibited. Around here the standard is to place burners (caldera and termo units) on the floor and not elevated as in some other jurisdictions.

Now waiting for final inspection and SEC approval. I started working this gas hookup in November. It is now March. Welcome to Chile.

Thanks to all who commented.

Ahh, is the door to the outside or into your building envelope? If into the building, normally the makeup air is from outside the envelope, no?? Preheating it with the hot air vented out of the room is normal these days.

Maximum temperature in the boiler room in Finland is 35C and for this excess ventilation has to be installed in some cases. In practise the temperature can get as high (there not here) is if the boiler and pipes are not properly insulated.

I tried to look why the maximum is 35 but didnt find an answer. Air density of course decreases with the increase of temperature but dont know if this is the reason.

nwdiver wrote:Ahh, is the door to the outside or into your building envelope? If into the building, normally the makeup air is from outside the envelope, no?? Preheating it with the hot air vented out of the room is normal these days.

The requirement here is for sala de caldera to be separated from main structure by firewall. In my case the access to the sala de caldera is via an outside door and all penetrations of the rated wall are to be firestopped (right.... just try finding intumescet firestop in this toy country, or anybody who even understands the concept). So there is no opportunity to preheat the makeup air. And for the other structures I have done or seen in North America where the furnace room was within the building envelope, the makeup air was not from the building but directly from the exterior of the structure. This has the desired effect of not sucking that carefully heated and distributed living space air.

Proper firestopper has been is used in the projects I have worked in here in Chile. The specialist company has come from Santiago or Conce to do it. For you to get somebody might be a tad difficult.

I know that In most EU countries they have the same regulations with the inlet air. It has to come directly from outside. Also most standards have the minimum area ( or diamerer) of the hole rfom where the air comes from .

If the air comes only from inside the house you can cause a temporary failure of the burner for example by slamming the door shut when the windows are closed.

For boiler rooms you should always have a Fire extinguisher on hanged outside the door , doors sould be made of fire proof material , like sheetmetal , ask any firefighter , sheet metal leas you feel the heat and judge if there is fire inside the boiler room , also you the door must have about an inch of clearance with the floor so air can enter , and and inch on top so hot air can escape , is also good to put on the lower part a Celosia , and if you want more security put a lock that can be unlocked from the inside and the outside , and a viewing port , that can be made of safety glass so in case of an explosion it wouldnt became deadly , fireproofing should be made of brick and mortar if you can afford it , 8 mm fibrocement covered with a layer of sheetmetal . Much like a house firewall .

nerdplanet wrote:For boiler rooms you should always have a Fire extinguisher on hanged outside the door , doors sould be made of fire proof material , like sheetmetal , ask any firefighter , sheet metal leas you feel the heat and judge if there is fire inside the boiler room , also you the door must have about an inch of clearance with the floor so air can enter , and and inch on top so hot air can escape , is also good to put on the lower part a Celosia , and if you want more security put a lock that can be unlocked from the inside and the outside , and a viewing port , that can be made of safety glass so in case of an explosion it wouldnt became deadly , fireproofing should be made of brick and mortar if you can afford it , 8 mm fibrocement covered with a layer of sheetmetal . Much like a house firewall .

The project we are talking about is for a residence and the original thread was about the combustion/makeup air supply rather than with the fire protection aspects you mention. If we were dealing with an industrial or commercial site then much of what you indicated might be appropriate though we would take a look at NFPA 101 for life-safety design for door installations.

In this case, for the residence, there is no need or requirement for a rated door since it opens to the outside of the structure. There is a continuous firewall of sheet metal and internit between sala de caldera and the exterior wall of the occupied space. Nobody could find any intumescent firestop in Chile so we poured concrete around the firewall penetrations, which is not ideal but it's still better than 99 percent of the residential structures in Chile. Thanks for the comments.