Consumer Product Safety

Accidents on Thawing Machine" (Calling Attention.)"

November 28, 2001

Accidents on "Thawing Machine" (Calling Attention.)

Accident information that a fire occurred in using a thawing machine (a device for thawing a frozen water pipe by making a current flow thereto and heating it) at home was reported (in total 16 cases) to the National Institute of Technology and Evaluation (hereinafter referred to as "NITE") from December 2000 to January 2001).
To prevent such accidents from occurring, NITE calls users' attention by releasing the contents of the accidents so far and the results of the cause unfolding in the NITE.

1. Accidents Occurrence Situations

  1. (1)Fires occurred during thawing water pipes or after finishing the thawing and houses were burnt down to the ground or parts of the houses were burned. (13 cases).
  2. (2)During thawing the water pipes, plastic bathtubs in bathrooms were charred (two cases).
  3. (3)During thawing the water pipe, an anti-icing heater, etc., were molten (one case).

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2. Origins of Accidents

According to the investigation of the fire station, though some accidents were terribly burnt so as not to specify the causes, in most of the accidents, when a water supply worker or a user thawed the frozen water pipe, a stainless flexible pipe* in a wall was overheated by the electric resistance difference and a fire broke out from a thermal insulation material.

* Stainless flexible pipe:
A stainless bellows pipe capable of being freely bent and mainly used for connecting the water pipe to a faucet.

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3. Matters Required Attention

Where a stainless flexible pipe exists on the way to the water pipe to be thawed, the portion may be heated by the electric resistance difference and become high temperature, which may cause a fire.( referring to Results of Cause Unfolding of NITE) At present, a maker of the thawing machine examines its counterplan for preventing the accident from occurring.
For persons using the thawing machine, please make contact with the manufacturer or an import maker of the thawing machine under use and confirm the safety using method.

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Results of Cause Unfolding of NITE

As for the confirmation method, the pipe in an unfrozen state was measured in assuming cases where the current is sequentially made to flow after the thawing by the long hours of use.

  1. (1)When feeding 10A current thereto, the stainless flexible pipe was heated and turned into red about 5 minutes later and when feeding 15A current, about 2 minutes later. Temperatures of the respective measurement points are as shown in the following table.

  2. (2)Confirmation method: Measured at three points as follows (measured at room temperature by placing them laterally)

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