I’ve come into a quandry. I’ve figured out my basic layout design for my standard gauge HO, but on paper, a 30in. radius curve in the largest available space in my basement pretty much gives me a giant oval. I need 30in.s at least to operate some Steam motive power with less movable trailing trucks.
Now, the good thing is, I can put in more curves and meandering branch-lines if only I run a double-track main between the cold air return and the hot air pipe of my natural gas (methane) furnace, around the gas main then back around and under the exhaust pipes of the hot water tank and the furnace to a potential hidden staging area.
The maximum space for the track and layout work is about 6 inches between things and I need to get the bench work within 18 inches of the exhaust tubes and furnace air intakes. The furnace is new 80% efficient. I plan to use nickle-silver, plastic tie flex track with plywood and pine benchwork (standard stuff), with lots of plastic and plaster for buildings and scenery.
If I proceed at minimum clearances, how long before I ignite my house, or I’m going to be OK?
Well, I am probably going ot get flamed here (ha, no pun intended) by the other experts for saftey, but here is my take…
If that is all it is, cold air down, hot air out. How hot is the air coming out of the pipe? I admit, I do not know much about furnaces. I am pulliing my knowledge of Arizona, and working around headers and exhaust sytems in cars…
But if it is 100’ or even up to 150’ or more, I think you could easily wrapp it up or insulate the section faceing your layout. You can buy section of heavy automotive insulateingmatt at a good hardware store. Some of which can be good for 400’ or higher In car exhaust or a header, sometimes even a stamped thin peice of metal will deflect several hundered degrees. Sometimes need to protect a starter, or floor board when an exhuast sytem has been raised for clearance. (I own a 4x4 shop)
All though, I would be really tempted to leave the bench work open under it. SO as not to build up heat under the layout. Then again, it hits 100-110" degrees in my whole gagrage for about 2 months out of the year and I dont have any problems… Check into it, but I think it is very feasible[8D]
Wrap the hot pipe like Canazar suggested, lose the ties, the flammable roadbed, and anything else that will burn, and keep all that’s left at least one inch away from the hot pipe, two inches would be better. Hit a commercial construction site and get some scraps of sheet metal studs, or find out who their supplier is and build your benchwork from those. Glue the rails down with CCA and live with any noise issues that causes.
Don’t park any trains along that stretch either, in fact, admoni***he passengers to roll up the windows and the crew to proceed as quickly through that section as safety permits. If you have any questions, ask a HVAC guy to take a look at it. A sixpack or even a $100 fee is less expensive than a new house, or even one melted train.
One other issue should be considered. Since you are running so close to the furnace and hot water heater, consider the possibility that these units may have to be serviced or replaced in the future. You might want to consider using removable sections in these areas that are put in place only during your operating sessions. Remember, a watch pot never boils until you leave the room.
The ductwork isn’t the problem–the cold air return and warm air supply. Most warm air does not get that hot. I would be more worried about the exhaust. The vent (exhaust) from both the furnace and the water heater gets VERY hot. You should look into double-wall (B) vent, which you can get materials 1" close too, or keep everything at least a foot away. You could also make a shield of extra venting.
In addition, most building codes require at least 18" (some require 30") of space in front of a furnace for work access and safety. Check with the manuals that came with the furnace.
I also say watch the exhaust. While you can wrap the hot air supply ( they make special duct insulation, you needent go to the auto parts store) your only choice is distance or double wall exhaust pipe. Remember, hot air rises, so if you have the distance UNDER the exhaust pipe, you might be ok. NO PLASTIC BUILDINGS anywhere near the exhaust!!! I would’nt advise trees, etc. in those areas either. I think paper ignites at around 200’ F, keep that in mind
Model that area as a section of desert. Just sand, rocks, and catus. [:D]
Have a rock ridge sticking up between the pipe and the track as a heat shield.
Make that area a canyon with rocks on both sides of the track. Use real rocks with a sheet metal backing as a heat shield for the rocks.
If it is a newer furnace the discharge air temps are probably not near as warm as an older furnace, maybe 130-140 degrees max. A quick way to tell would be to put a small oven thermometer on the closest register and see just what it is putting out. I’d say if you did add a double wall or insulate the pipe you’d be OK.
BUT! Two problems- the first would be the need to service the furnace or shut off the gas main in an emergency like Leon mentioned- not really what a technician wants to see, he has to crawl under benchwork to try and get to the filter access or blower motor. And there may be city codes that regulate it also.
Second, whatever you use in the area will be subjected to a raised temp that will dry out and warp wood, cork, whatever. Longevity wise might be a problem? If I was going to do it I’d even keep it to a single track past the warmest section- maybe mount it on a steel stud like a bridge, glue it down with some hi temp RTV. It wouldn’t be pretty but would serve the purpose.
You live in Jamestown. Your furnace will be going like a blowtorch for six months each year. You had seven feet of snow just this month. An air discharge temp of even 140 degrees is enough to slow-cook a pot roast. So at the very least you need a heat shield.
Have you seen your latest gas bill? If it’s as big as mine, then the question is moot. National Fuel gets first dibs on the train money, at least until spring.
TPatrick hit one nail on the head – the gas bill. But I still need to plan if I’m ever going forward with a layout.
DBDuck: I don’t know if it matters but the ambient temperature of the room hangs in at around 58F through the winter, 65F in the Summer and too hot for an outstretched hand about six inches above the exhaust pipes for more than a couple of seconds.
Let me do some re-drawing to see what If I can use the same solution around the furnace and hot water tank but using your suggestions. Keep them coming. There is an answer. There always is.
Many of the new high efficiency furnaces have exhaust gasses so cool they are vented out the side of the house using PVC pipe. If you have one of those furnaces I doubt that heat would ever be an issue.
I agree with Leon… you would want to make sure there is adequate access to the furnace and hot water heater for any maintenance that might be needed.
You need to keep your house insurance agent, the fire marshall and the HVAC repairman happy by not violating any local building codes. Find out what they are. And on a more practical note, your benchwork and trackwork are going to be moving all over the place when you temperture cycle them all the time. Could be a maintenence headache.
What’s national/local code say? For some reason, I’m thinking that 2’ of clear space between anything and the furnace is what’s “legal”, but I’d like to hear that from an expert (or better yet, the code itself).
Don’t forget access TO the furnace. Not only will you need to be able to change the filters occasionally, but they DO occasionally break down. You’ll want a good chunk of the layout around the furnace to be easily removeable, so a HVAC repairman can get to it without having to be a gymnast (and they tend to be on the large size!)
I agree with Leon and Jerry allow enough room to access and replace the hot water tank and furnace. I live about 80 miles from your area, Jamestown, Pa. When I built my G scale layout (56ft by 26ft) I put in a removeable bridge to access the hot water tank and another bridge next to the furnace. The layout is only 5 years old and I have not needed to remove the bridges, but I know I planned for the situation.
Years ago I saw a guy build the horseshoe curve in his basement. He modeled all 4 tracks and it was really great. The furnace quit running and he could not get a repairman to crawl under the benchwork to get to the furnace. He had to tear down enough of the layout that they could walk to the furnace. He never rebuilt the layout, he built a new one and the furnace and hot water tank were accessable.
i have a similar but hotter problem. my layout is built around the walls of my family room and will be continous running except that the track will have to be 14" behind and 1ft over my wood stove which right now is burning at 500 to 550 degrees. the standard is a minimum of 18" from the stove to anything combustable. so no continious running from nov to april for me. the exhaust of a gas fired heater will be somewhat less than a wood stove. you can get a small thermometer with a magnet at a stove and fireplace shop to check the temps. you can also shield the layout by mounting some sheetmetal 1" from the layout to provide an airspace between it and the wood in the area of the exhaust.
Check your local building codes. Quite often, hot water tanks and occasionally furnaces do need to be changed. Inside the furnace are controls which need servicing. Plan ahead.
Look into doulbe walled, insulated metal heat shielding. You could use that as a tunnel. Use a small 12v metal fan to circulate the air to help keep the area from getting too hot. Also, like said by the others, check your codes for clearances, and make the furnace and water heater accessable for service, repairs or replacement. As long as you do not break or bend any codes, your insurance man will not have to worry, and you can still keep your coverage at a low risk rate.
My furnace has the clearance requirements posted right on it - 2 inches per side. (New furnace, installed last January.) The layout goes between the furnace and the hot water heater, but the section of benchwork is removable so the hot water heater can be replaced if necessary.