Asbestos and Hot Water Cylinders

By Stan G. in Removal

In the peak of asbestos manufacturing, asbestos was used in many different ways, from textured paint to durable wall materials and cement. However, due to both its insulating properties and high heat resistance, one of the largest markets for its use was as insulator and liner for residential buildings' heating systems in order to reduce energy costs and prevent fires. Although asbestos can be difficult to identify with the naked eye, there are certain traits that make it easy to recognize on water heaters. For example, the mineral can be spotted in the insulating blanket within the metal cover and in the tank jacket placed around water heaters.

If a water heater was manufactured before 1980 when asbestos was touted as a miracle product, it can contain the following asbestos-based components:

  • Insulation
  • Gaskets
  • Reinforced plastics
  • Wiring
  • Insulating boards

Asbestos - Commonly Used as Covering for Old Water Heaters

To have water warm enough to take a hot shower, or use your dishwasher or washing machine, you need a water heater. Appliances called water heaters, hot water cylinders, hot water tanks, boilers, heat exchangers, use a transfer process through an energy source to heat water above its initial temperature. They look like big metal cylinders that are often consigned to a laundry room, garage or basement. An insulation blanket can make water heaters more energy-efficient; it is estimated to reduce standby heat losses by 25% - 45%.

Asbestos was commonly used as covering for water heaters and boilers. Hot water pipes were also wrapped in asbestos after they were installed. This wrapping could follow the piping all the way throughout the structure, meaning there are many points in a home where asbestos could be present. That type of asbestos infused fabric or cardboard called laggings can disintegrate over time and release fibers into the airstream.

How to Visually Identify the Installation Date and Manufacturer of a Water Heater

Although the age of your water heater tank is not the main factor in determining whether it's time to replace it, it may be useful in finding the date the insulation was applied. Verifying the installation date doesn't necessarily prove the age of the water heater since some units are pre-owned, but it does help to rule out the possibility that it contains asbestos.

The easiest way to find an answer to the question of how old is my water heater is to locate the manufacturer's label and serial number - the long sequence of digits and letters found printed on the side of your water heater. If it's an older and discontinued model, you can attempt to find the date when they stopped making these water heaters. If they've stopped making that model prior to 1980 then at least you can assume that your water heater has materials that contain asbestos.

Companies that manufactured water heaters include:

  • American Standard, Inc.
  • Allis-Chalmers Manufacturing Company
  • U. S. Mineral Products Corporation
  • Aqua-Chem, Inc.
  • Columbia Boiler Company
  • Combustion Engineering
  • Crane Co.
  • Riley Stoker Corporation
  • Foster-Wheeler Corporation
  • Henry Vogt Machine Co.
  • Parsons
  • Weil-McLain
  • Zurn Industries, Inc.
  • Kewanee Boiler Corporation
  • Babcock and Wilcox Company

How to Identify Asbestos in Your Water Heating System?

Asbestos is known for its heat resistance and thermal insulation properties and it was used to help insulate pipes, boilers, ducts and tanks in homes between 1930 and 1980. Chrysolite or white asbestos was the most common form of asbestos due to its flexibility and ability to be used as a joint-compound in plaster mix known as lagging, this was used to cover and insulate pipes and water heaters.

Whether a garage or a home basement, if you're looking at a home outfitted prior to the 1980s, you may want to give your water heating system a closer look. The visual identification of asbestos coating used to insulate older heating systems can be a certainty in many cases. Asbestos insulation looks like white-gray material that people often compare to corrugated paper. Although it has many different appearances, asbestos insulation on heating pipes can usually be identified by its flaky and powdery appearance.

Some older hot water systems contained asbestos "millboard" to insulate the electrical connections behind the removable access panel. Very old systems had the entire tank internally or externally insulated with asbestos. These hot water heaters should be replaced as the tanks corrode.

If you are a DIY home renovator thinking about removing asbestos-based insulation covering the water heater and pipes yourself, there are several precautions you must take before getting to the removal per se. For information on how to safely perform asbestos removal, we recommend you to read our Asbestos Removal page.

Why Should I Test Products in My Home for Asbestos?

It is often impossible to tell whether asbestos is embedded in a material, as the fibers are too small to be observed with the naked eye. Exposure to asbestos is responsible for serious respiratory conditions, so thorough testing is required to ensure your home is asbestos-free.