Trying To Heat The American Legion Building
Thanks in advance for your replies.
A little background on what we have to work with..
The local American Legion building has been erected in a number of builds throughout the years. It started with a 30' x 30' building (this is the kitchen area) with windows that fold out to serve food at our annual community picnic. At some point the members added an additional 50' of pole barn to one end of the building (this is storage only). A number of years later they added another 100' long pavilion to the other end of the building and at some point this was enclosed (this is the commons area). We now have a building that is 180' long x 30' wide with ceilings that are 7 1/2 ' high. A few years back the Legion hired a contractor to come in and blow cellulose insulation into the walls and attic spaces of the kitchen and common areas. The current furnaces (2) are ancient down draft units that a member of the community donated when he upgraded the units in his home. A volunteer heating/cooling contractor placed the units along the walls inside the commons area of the building with the duct work running along the floor by main walls where seating should be located (the duct work sticks out 2' from the walls and 8" high).
My questions are these ..
We would like to place one or two up draft furnaces in the storage unit mentioned above with flexible duct work running thru the rafters of the attic to heat both the kitchen and commons area... the heated area will be 130' x 30' x 7 1/2' .. (approximately 30,000 cubic feet)
Because the building is so long and narrow with low ceilings, can one furnace heat the entire place comfortably? If we use one unit, should the contractor that we hire make the duct work diameter get smaller as he gets closer to the far end of the building (I saw this in the open ceiling of a local gas station)? Should we run 2 units with each heating a different end of the building and being controlled by a thermostat on that respective end of the building? Should we run 2 units with duct work side by side the length of the building? What size unit or units should we be trying to locate?
We have the opinion of a member that is an HVAC contractor, but the rest of the membership has a different opinion.
The kitchen needs to be on its own system. Its has its own heat source(grille, broiler,dish washer, ovens, etc) when its open, and needs heat when it is not.
That leaves you with just the 100' x 30' add on.
Although you could use 1 standard/resi furnace to heat it,(if your not installing to code). 2 furnaces would be better.
Are they going to consider A/C down the road?
Are they going to have the code required fresh air for the people load?
Yes, with duct work that long, it needs to be reduced.
Please see blue text above ..
Originally Posted by beenthere
That will depend on the type and how much exhaust the kitchen has then.
Can't say what size furnaces for sure over the internet. Too many possibilities.
Including how much exhaust and make up air the kitchen has.
The fresh air is for the people.
So how many people will have a bearing on size also.
You may be able to get away with a 140,000BTU. Or need 280,000 BTUs.
What size are the current furnaces. And do they run continuous, or cycle on and off, during the coldest days/nights of the winter.
I would still try and have the kitchen as isolated as possible. You need to have it in a negative pressure.
When you say they are going to be in a storage room, what do you store in there????? Chemicals, or combustibles???? If you do, you need to build a seperate room in there just for the furnaces. Fire and chemicals don't mix well with flames, even if it's well vented.
Is there a way to put a packaged unit outside somewhere???? Or locate a rooftop unit somewhere?
See the blue text above
Originally Posted by beenthere
See blue text above
Originally Posted by tinmarine
Last edited by LegionHeat; 10-26-2008 at 05:41 PM.
Best way to determine actual size required is a commercial load calc has to be run on the building.
The fresh air is per person, and yes, it must be fresh, as in outdoor air.
You can get a horizontal furnace for an attic.
Originally Posted by LegionHeat
You can also have a rooftop unit that is a package unit that will work as both heat and A/C, that can be ordered so you can control the amount of fresh air being brought into the building, then you can have an exhaust fan for the kitchen area. If it were me, from what you described, this is PROBABLY the route I would go, given the info you presented. HOWEVER, I haven't seen the building, so I can't say for 100%. They have all kinds of different units that would work, don't constrain yourself to furnaces.
I usually don't do this, but -
You should hire an engineer to set this up.
In our area, any kitchen used for a commercial purpose needs a Class I grease duct and dedicated hood with fire suppression. Doesn't matter if it's actually residential appliances.
This hood will draw quite a bit of air that needs to be made up and conditioned. Doesn't matter how infrequently you use it.
The meeting hall also has large fresh air requirements - again - doesn't matter how infrequently you use it. Although operable windows can help you here.
Unless this is located in a land of no codes, you really should get a local engineering firm there to point you in the right direction. The up-front cost you spend on engineering will pay back with a well set up system that will not violate codes and potentially harm people. Seriously.
I'm not saying this is definitely the case - but sometimes that HVAC guy you have in the club could do you much more harm than good, trust me.
I have to agree with the engineer being brought in on this one. Being a commercial/public building being used by the public your organizations liability is tremendous if something were to go wrong with an installation that was not done with state approved plans and installed by someone with insurance.
Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.
I completely understand this line of thinking, but I have to say a couple of things. We have been using the current setup for about 30 years .. no fresh air whatsoever, the units (2 updraft air conditioner and 2 downdraft furnaces) are sitting right in the commons area and the duct work runs along the floor 2 feet from the walls on two sides the length of the room (people actually have to take turns walking between them and the tables) the returns are simply grates mounted on the side of the furnace.
Originally Posted by firecontrol
The licensed heating/cooling guy seems to think that it is just fine the way it is currently set up (his deceased father set it up originally) .. even if we install new units. The rest of the membership want the units out of the room and we are trying to get this all done on a donation/volunteer basis as most of our money goes to buying flag poles to display the flags of our fallen soldiers at the cemetary and on the Legion grounds, sending money to support efforts that assist injured veterans and their families, and to activities that support our troops in the middle east.
I know that everyone here is trying protect the best interest of the organization and their liability, but if we don't do anything at all because we cannot afford to pay an engineer we will still be in violation of codes the same as we have been for 30 years.. with lower efficiency hvac units that end up costing us alot more due to the cost of propane, are very inconveniently located, and are surely more dangerous to the people using the building than would be the case if we upgraded the units and put them out of the commons area.
Thanks to everybody that has taken the time and consideration to respond to this post .. the first few replies gave me some very valuable information..