EFFICIANCY PAYBACK

Jim Davis

CO Stories

A few years ago I was called to Dubuque, IA, to investigate a 6 family condo where all occupants had to be treated for CO poisoning. But is was not until after the Head building Inspected required a combustion air pipe be brought into the mechanical room. Upon investigation it was found that this pipe running to the attic was a major exhaust. After making recommendations for induced combustion air from another source the inspector said that was not acceptable to him. Someone else recommended another way to supply combustion air that would have been even more dangerous. The inspector said that wasn't his problem!!
In Michigan a baby died and the parents were being held under suspicion. A furnace in a closet with a full louvered door was suspected of the problem. The louvers were clean and the furnace worked just fine with the door open. But as soon as it closed the furnace started to starve for air and eventually produced CO levels in excess of 2000ppm. To find a schedule of classes, go to www.ncinstitute.com. Obviously if all I was trying to do is sell training, I wouldn't have had to be ask for this infor.

Al D'Ambola

Proper air flow readings

To measure correctly with a pitot tube are you taking your velocity pressure reading one at atime and sq rooting that velocity pressure times the velocity pressure by 4005=fpm. On any rectangle traverse you need a minimum of 16 readings across a duct. If a lot of turbulence in a duct you need more readings.

Steve Ebels

> To measure correctly with a pitot tube are you

> taking your velocity pressure reading one at

> atime and sq rooting that velocity pressure times

> the velocity pressure by 4005=fpm. On any

> rectangle traverse you need a minimum of 16

> readings across a duct. If a lot of turbulence in

> a duct you need more readings.

Steve Ebels

No

I'm just using the chart that came with the gauge from Dwyer instruments. It was my dad's. I have no idea where he got it or how old it is.

ScottMP

Jim

I had a little trouble following your first story, but the second situation dos'nt seem to fit our discussion.

Your statement was that jobs done to "code and manufactures specifications" were the problem. In MASS a louvered door is not acceptable to provided proper make air and I believe most manufactures would not allow this ?

Am I wrong ?

Thanks for the reply

Scott

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Steamhead

And

how big were those louvers?

Did they have enough rated capacity to supply the air needed for a furnasty of that size?

How much free area did they have?

You say they were clean, but was the free area reduced by clogging with paint or something else?

What was the source of air that was available at the louvers?

What was the furnasty's rating?

What Code was in force and what did it say regarding this situation?

These are some of the things I'd want to know when evaluating a problem like this.

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Jim Davis

The first story discusses how a job that was initially installed that didn't conform to code, became dangerous after a code official insisted. The sad part was that after he was shown this he didn't care.
Most states allow full louvered doors and in some the return air grill is installed right below it. Other the return is just around the corner.
The furnace with the full louvered door was 50,000 BTU. The free area of the door calculated to be 50% excess.
Other states all a return grille directly on the side of the furnace with no duct or additional make-up air.
One of the first jobs I usually discuss in class is a mechanical room in a hotel. When testing the two commercial water heaters, they were found to be not venting and making in excess of 1000ppm of CO. The combustion air grille was partially blocked with a piece of wood. When the board was removed the venting problem applified and the CO level doubled and tripled, as witnessed by the whole class that left the room immediately. Air was coming in yhe grille.
A non-related story (CO not the problem) is about a boiler in a wood refinishing plant that was rusting out every 18 months. A contractor recommend the boiler needed to be isolated from the chemicals in the plant and outside air brought in. A mechanical room was built and outside air brought in a the boiler rusted out in 6 months. The rest of the story is too complicated to give all the details here.

Jim Davis

In court cases city inspectors are brought in immediately to confirm if the installation was up to code. According to them it was fine. Louvers, doors, pipes are poor sources of combustion air if their direction cannot be controlled.