ELECTRIC HVAC HEATERS: BACKUP SAFETY PROTECTION REQUIREMENTS
TABLE OF CONTENTS
The attached materials ("Tabs") relate to the issues addressed in the Cover Letter
and Safety Bulletin. These materials are available to provide additional,
more detailed information on the issues ("Presentation") or to support the
representations made therein ("Reference").
TAB 1: Backup Overheating Protection in Unitary Electric Heaters
TAB 2: Industry Response & UL1995 Misinterpretation by Certified Lab
TAB 3: Response to Industry Misinterpretation
TAB 4: Temperature Ranges relating to Heater Operation
TAB 5: Backup Protection Devices must be Reliably Safe
TAB 6: UL1995 Safety Standard - October 2011
TAB 7: Photographs
TAB 8: Recent Collection of Some Failed Devices
REFERENCE: The automatically resetting controls in this photo have each failed
in the closed circuit position. This sample contains exemplars returned by some
installers who serviced Warren heaters in which the voluntarily incorporated
backup protection was triggered by excessive temperatures and, in turn shut down
the heater before any fire could occur.
TAB 9: Product Bulletin for ARTLC & Non-Resettable (Replaceable) Device
TAB 10: Home Fires Involving Heating Equipment
REFERENCE: NFPA 2012 Report: Home Fires Involving Heater Equipment (by National
Fire Protection Association). National study identifies home fires in 2006-2010
caused by electric powered central heating equipment. The report identifies
3,390 fires are caused by electric central heaters in American homes each year.
While 540 fires were reported as caused "Automatic Control Failures", precisely,
other more general causes reported could, and probably do result from the
unprotected failure of the automatic controls. For instance, "Failure to Clean"
reduces air-flow and the resulting hazardous temperatures create a fire (220
fires per year), or "Unclassified Mechanical Failure or Malfunction" certainly
would describe the failure of the contacts to open on an unprotected automatic
control, as well as "Unclassified Electrical Failure or Malfunction" (1,270
fires per year, combined), etc. (See page 68).