Definition of a \"draft hood\"

Mark Hunt

From "GAMAzine" Fall 2004 page 24, quoting the 2002 "National Fuel Gas Code"

*Draft Hood- A non-adjustable device built into an appliance, or made a part of the flue or vent connector from an appliance, that is designed to: (1) provide for the ready escape of flue gases from the appliance in the event of no draft, back draft, or stoppage beyond the draft hood". HAHAHA! Get me two!

"(2) prevent a back draft from entering the appliance, and" Cool! No more worries about pilot light going out ah?

(3) neutralize the effect of stack action of the chimney or gas vent upon the operation of the appliance."

So no matter what goes wrong...........it will not fail to operate!

Whew!

Like Jim Davis says, CO victims die warm and clean.

Heat and hot water without regard to safety. Comfort first.

Mark H

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Dave Bush

Makes ya wonder

How many bottles it takes to write some of that stuff...

Unknown

Mark, would you recommend

removing or blocking off every draft hood? I assume that you would then install a barometric on all appliances with a draft hood. Is that correct?

How many gas conversion burners would you do this on? Remember on some atmospheric coal to gas conversions the ANSI standard for installation of those burners required a flue reduction with an adjustable slide in the draft hood to be able to adequately control draft. In doing over 3,000 residential gas conversions and attempting to use barometrics on some of them the barometric would not work adequately.

There are also some designed equipment that this will create problems if they have the draft hood removed.

The draft hood is not always bad so it requires us to be careful with our education of everyone.

A lot of commercial applications work much better with barometrics. That is not always the case with residential equipment

By the way down drafts cause very few pilot outages. It is only in extreme conditions that eventually contaminates the air for combustion in the equipment room that a downdraft would be blamed for pilot outage. There are hundreds of reasons why pilots go out.

Mark Hunt

Yah


Me too.

But that is an "industry accepted standard".

I don't make this stuff up............I just read it.

And then I report it.

Mark H

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Mark Hunt

I posted a definition from a book you quote often


And the situations you mentioned are quickly becoming extinct, however, the "code" remains for eternity.

Please check your e-mail.

Mark H

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Larry Weingarten

The historical perspective...

on this could be that the draft hood was designed and the code was written mostly to address the problems of downdraft and pilot outtage. It may have been written when 100% safeties were not commonly used. Certainly buildings were leakier then, diluting the products of combustion that did spill indoors.

Buildings and equipment have changed... and the written word hasn't. Time for a rewrite perhaps? ;~)

Mark Hunt

I'll agree with that


Thanks Larry.


Mark H

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