Direct Vent Question

MikeyB

I had posted this question on Tim's Gas Heating Section and wanted to see if I could get some more input on the Main Wall. If the vent termination and air intake for a sealed combustion cast iron boiler (not a mod-con) was "close" to the 12 inch min clearance from the ground level and another say 12 inches for a snow level (for a total of 2 feet off the ground) and you wanted to give it some more clearance (just to be safe), rather than turning the terminations up on a vertical (to give it that extra height, and now would have to add a condensate tee for the vent) could you dig a hole (under the terminations)  about a foot or so deep and install  a window well enclosure around the hole (not the style that will totally enclose the area, just the front of the hole), to prevent anyone from falling in the hole & have that extra area for more snow accumulation? Has any one ever seen or heard of this before, Thanks

Brad White

Here in MA

we have a requirement to install CO detectors and signage if the vent terminates less than seven feet above grade.  (Much more to it than that, but just a synopsis on topic.)



I mention this out of recognition that snow does not fall straight down but drifts and two feet above grade is not good insurance in my book.



(CO detectors are to me essential, not just when you are venting low. That is an entirely different discussion.)



The window well you describe is just a spec to be filled in a good snow storm, when you need it most. Personally, I would do what it takes to get it up and away. The 12 inches is just a minimum.



I am sure others have much more to add than I could say.



My $0.02 anyway.



Brad

icesailor

In MA:

Don't try to re-write the laws of physics.

Run this bad idea past the gas inspector and the boiler manufacturer.

In Massachusetts, the person who takes out the gas permit is required to do the venting. No exceptions. If the boiler manufacturer does not show this installation (vent termination in a hole) it isn';t legal.

You do not have enough money nor do I have enough insurance to get ME to gas pipe this and be responsible for this proposed venting.

Jack

Okay,

My previous post in Tim's section was to abrupt. I get the calls to inspect improperly vented appliances. I'm a rep. At least 60-75% of the DV jobs I see have a vent problem. As well I have been doing the same for a power vent manuf for a long time. If you are looking to create space you need to recontour the lawn for clear air flow. How far? I'd tell you probably 4' on either side and at least 6' in fornt. Every system has a personality. What you want to do MAY work, but without a lot of work I think you are building a problem for yourself, the next guy who gets called to repair and definitely the homeowner. Do it once, do it right and get on to the next job.

MikeyB

DV

Thanks for all your posts guys, I agree will all of you, and especially w/the CO Detectors Brad. There is no intention to terminate the vent/air intake in a hole, both terminations will be close to 2 feet above grade to begin with , then addindg another foot or so below grade to give more room for the snow (with the idea of a window well enclosure) , just a thought. Nice to see you back posting Brad.

Henry

Window wells

In Canada, we do not accept window wells as grade. They are wells. Therefore your measurements must be of the surrounding area for your clearances. At last weeks sub-commitee meetings we had discussions about the snow clearance. Across Canada snow accumilation is different for each area. For now we left the code as it is written. Each installer is responsible to find out the average yearly snow accumilation for his area and then vent accordingly. This will vary from each area and city.



Henry

Tim McElwain

Mike, it is my recommendation

and was also policy when I was with the gas utility that the vents had to terminate 30" above grade. This was back when most of the vents did not have specs that allowed vertical venting through the roof or using the old chimney as a chase. I was the one who determined the 30" and it came from the blizzard of 1978 here in New England when we had an average snowfall of 30" during that blizzard (more in some areas) I felt 30" was a good point of reference. Really the higher the better.



I did not say too much when you posted in my area as I wanted to see what all the installers felt. I feel that the well would just fill up or it would allow the customer to place one of those well covers over it and make an even worse situation

MikeyB

DV

Thanks Tim, I also remember attending a class a Manufactures Rep for Lochinvar was holding last year on Long Island and he had mentioned 30 inches as well, (The 12" min plus another 18" for New York snow fall) knowing that there was less than the 30 inches total, this  why I wanted to ask to see what others thought of trying to gain an additional foot or so when looking to avoid going up on a vertical, thanks again guys for all your input.

icesailor

DV/Wells:

Another thing to consider about vent locations that are not in the codes are locations in relationship to the prevailing winter storm direction. The manufacturers suggest not positioning the vent outlet where the prevailing winds come from. That's easy. Where I work, the wind comes strongly from every direction during the year. But the prevailing winds in coastal New England are from the NW. So, positioning the outlet may seem like a good idea. Except that Nor'Easters start from the SE and clocl to East and NE. When the wind is in the NE, dhe drifts form in the lee and drift up against the South and SE side. The more the snow and the higher the winds, the bigger the drift.

It is really a problem and should be considered when determining how high to make the vent termination in snow areas.



Just my opinion.