UL 521 BULLETIN-2010
UL Standard for Safety Heat Detectors for Fire Protective Signaling Systems

Standard No.

UL 521 BULLETIN-2010

Release Date

2010

Published By

Underwriters Laboratories (UL)

Status

Be replaced 2014-05

Replace By

UL 521 BULLETIN-2014

Latest

UL 521-2021

Scope

These requirements cover heat detectors for fire protective signaling systems intended to be installed in ordinary indoor and outdoor locations in accordance with the Standard for Automatic Fire Detectors@ NFPA 72E. Heat detectors covered by these requirements employ either normally open contacts or normally closed contacts@ provide an electronic signal@ or consist of a heat-sensitive cable. The requirements do not cover heat detectors for journal-alarm or unit-alarm devices. Deleted October 3@ 2002

UL 521 BULLETIN-2010 history

• 2021 UL 521-2021 UL Standard for Safety Heat Detectors for Fire Protective Signaling Systems COMMENTS DUE: FEBRUARY 18, 2008
• 2017 UL 521 BULLETIN-2017 UL Standard for Safety Heat Detectors for Fire Protective Signaling Systems (COMMENTS DUE: August 2@ 2017)
• 2016 UL 521 BULLETIN-2016 UL Standard for Safety Heat Detectors for Fire Protective Signaling Systems (COMMENTS DUE: SEPTEMBER 26@ 2016)
• 1970 UL 521-2016 UL Standard for Safety Heat Detectors for Fire Protective Signaling Systems COMMENTS DUE: FEBRUARY 18, 2008
• 2015 UL 521 BULLETIN-2015 UL Standard for Safety Heat Detectors for Fire Protective Signaling Systems (COMMENTS DUE: MARCH 16@ 2015)
• 2014 UL 521 BULLETIN-2014 UL Standard for Safety Heat Detectors for Fire Protective Signaling Systems (COMMENTS DUE: MAY 23@ 2014)
• 2010 UL 521 BULLETIN-2010 UL Standard for Safety Heat Detectors for Fire Protective Signaling Systems
• 2009 UL 521 BULLETIN-2009 UL Standard for Safety Heat Detectors for Fire Protective Signaling Systems (COMMENTS DUE: November 02@ 2009)
• 2008 UL 521 BULLETIN-2008 UL Standard for Safety Heat Detectors for Fire Protective Signaling Systems (COMMENTS DUE: FEBRUARY 18@ 2008)
• 2001 UL 521 BULLETINS-2001 10/19/2001 (16p)
• 2001 UL 521 BULLETIN-2001 UL Standard for Safety Heat Detectors for Fire Protective Signaling Systems
• 1999 UL 521-1999 UL Standard for Safety Heat Detectors for Fire Protective Signaling Systems Seventh Edition; Reprint with Revisions Through and Including July 20, 2005
• 1993 UL 521-1993 UL Standard for Safety Heat Detectors for Fire Protective Signaling Systems (Sixth Edition)