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Negative pressure environments

Negative pressure can occur when there isn’t enough ventilation in the home and an exhaust fan is operating.

Negative pressure environment

Negative pressure can occur when there isn’t enough ventilation in the home and an exhaust fan is operating. Essentially, it has the effect of drawing air from any external opening in a house, including gas appliance flues and chimneys. This creates a problem with the operation of an open flued gas heater – and particularly a faulty one – because it means that dangerous gasses, such as carbon monoxide, can be drawn into living spaces via the gas appliance flue or chimney.

Simple steps you can take to resolve negative pressure

Victorian winters can be very cold, so it’s important to keep warm. If you have an open-flued gas heater there are some simple steps you can take that will keep you and your loved ones safe:

  • Get your gas heater serviced once every two years
    To ensure your heater runs safely and efficiently, and includes a check for negative pressure by your gas plumber.
  • Don’t operate exhaust fans at the same time as your heater
    Your rangehood, toilet or bathroom fan can create a ‘negative pressure’ effect, drawing carbon monoxide into living areas.
  • Ensure you have adequate ventilation
    While it’s not necessary to have windows and doors wide open on a freezing cold day, ventilation is important to ensure carbon monoxide isn’t drawn into a living space.
  • Don’t leave your gas heater on all night
    Don’t leave the heater on for extended periods or when you don’t need it.
  • Consider installing back-up measures such as a carbon monoxide alarm
    Carbon monoxide alarms can be a useful back-up precaution, but should not be considered a substitute for the proper installation and maintenance of gas heating appliances.
  • Never use your outdoor heating appliances indoors
    Outdoor heaters, such as patio heaters, barbecues, coal heaters and fire pits release carbon monoxide into the surrounding atmosphere. Carbon monoxide is lighter than air and can disperse more readily outdoors, but can be fatal if used indoors.

Understand what a negative pressure environment is, its effect on open flue gas heaters and how to test for it and mitigate it.

Date: 01/02/2023 11:06

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Reviewed 30 January 2023

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