How are drafts measured?

Asked By: Anni Maaroufi | Last Updated: 5th February, 2020
Category: home and garden indoor environmental quality
4.9/5 (77 Views . 30 Votes)
Draft intensity is measured in “inches of water”. Just as a mercury barometer is used to measure atmospheric pressure in inches of mercury, a draft gauge is used to measure draft intensity (pressure) in inches of water. Natural Draft is thermal draft.

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Similarly, you may ask, what is a draft test?

Performing a Draft Test. Draft is required to remove the flue gasses from the heat exchanger or draft hood on all atmospheric and draft induced appliances, and most power burner equipped appliances. All appliances requiring draft are required to have and maintain draft during operation.

Similarly, how does a draft regulator work? Draft regulators or barometric dampers are devices used to regulate the draft on oil-fired furnaces, boilers, and water heaters. You adjust the weight to control the amount of the opening of this damper which in turn controls the amount of excess air that can enter the flue and chimney when the oil burner is operating.

Also to know, what is positive and negative draft?

A positive draft means the angle of the face, with respect to the direction of pull, is more than the reference angle. A negative draft means the angle of the face, with respect to the direction of the pull, is less than the negative reference angle.

What is a draft gauge used for?

draft gage. [′draft ‚gāj] (engineering) A modified U-tube manometer used to measure draft of low gas heads, such as draft pressure in a furnace, or small differential pressures, for example, less than 2 inches (5 centimeters) of water.

17 Related Question Answers Found

What is stack draft?

The combustion flue gases inside the flue gas stacks are much hotter than the ambient outside air and therefore less dense than the ambient air. That movement or flow of combustion air and flue gas is called "natural draft", "natural ventilation", "chimney effect", or "stack effect".

What is induced draft?

Definition of induced draft. : a draft produced by a suction steam jet or fan on the stack side of a furnace.

What is Draft pressure gauge?

Definition of draft gage. An instrument used to measure the small pressure differentials below atmospheric; e.g., an inclined manometer to measure the pressure difference between a flue and the atmosphere for combustion control.

How can I improve my chimney draft?

Warm the Metal Chimney
  1. Roll a piece of newspaper into a tube.
  2. Hold the flame directly under the flue system.
  3. Light a fire in the firebox immediately after warming the flue system.
  4. Place a brick under each leg of the fire grate.
  5. Light the fire and watch to see if the smoke goes up the flue system.

Does a longer chimney increase draft?


The rising hot gas creates a pressure difference called draft which draws combustion air into the appliance and expels the exhaust gas outside. Two factors affect the amount of draft produced by a chimney. 1. Height: the taller the chimney, the more draft it will produce at a given temperature difference.

Does a chimney cap Reduce draft?

In addition to protecting your fireplace system from moisture, animals, and debris, chimney caps can also help improve fireplace drafting. The presence of a chimney cap does not eliminate draft issues, however. There are a number of draft issues that can occur even with a chimney cap.

How do you know if your chimney is open?

Perform a visual check.
Using a flashlight, poke your head inside the fireplace to look up into the chimney. If you have a throat damper, you can tell if it is closed if you see a barrier above your head. If you can see up into the flue, the damper is open.

How does a Draught Stabiliser work?

A draught stabiliser is a factory-made counter-balanced flap device admitting air to the flue, from the same space as the combustion air, to prevent excessive variations in the draught. NB A 'draught break' is an opening formed by a factory-made component into any part of the flue serving an open-flued appliance.