Category three warning systems

  • Thursday, September 28, 2017 6:33 PM
    Message # 5285431

    5.3.9 Category 3 Warning Systems. Category 3 warning systems shall comply with 5.2.9 except as follows:

    1. (1)  Warning systems shall be permitted to be a single alarm panel.

    2. (2)  The alarm panel shall be located in an area of continuous surveillance while the facility is in operation.

    3. (3)  Pressure and vacuum switches/sensors shall be mounted at the source equipment with a pressure indicator at the master alarm panel. 

       My question is what would you consider a pressure indicator in the statement above? 

    Last modified: Thursday, September 28, 2017 6:35 PM | Don Holden
  • Thursday, September 28, 2017 8:50 PM
    Reply # 5285529 on 5285431
    Al Moon (Administrator)

    What Edition NFPA 99 would you like to review:

  • Friday, September 29, 2017 6:15 AM
    Reply # 5287265 on 5285431

    Right answer Al, but I think the answer is pretty much the same for all - an idiot light.   The term "indicator" is normally used in this way, particularly in older versions of the document.

  • Friday, September 29, 2017 6:42 AM
    Reply # 5287274 on 5285431
    Al Moon (Administrator)



    Definition of indicator


    1 :one that indicates: such as

    a :an index hand (as on a dial) :pointer

    b (1) :gauge 2b, dial 4a

    (2) :an instrument for automatically making a diagram that indicates the pressure in and volume of the working fluid of an engine throughout the cycle


    2 a :a substance (such as litmus) used to show visually (as by change of color) the condition of a solution with respect to the presence of a particular material (such as a free acid or alkali)

    b :tracer 4b


    3 :an organism or ecological community so strictly associated with particular environmental conditions that its presence is indicative of the existence of these conditions


    4 :any of a group of statistical values (such as level of employment) that taken together give an indication of the health of the economy     


  • Friday, September 29, 2017 11:44 AM
    Reply # 5287650 on 5285431

    NFPA 99 2015 Final Line Pressure Regulators. All positive pressure supply systems shall be provided with duplex line pressure regulators piped in parallel with the following characteristics:

    1. They shall be provided with isolation valves on the source side of each regulator.
    2. They shall be provided with isolation or check valves on the patient side of each regulator.
    3. A pressure indicator(s) shall be located downstream (patient or use side) of each regulator or immediately downstream of the isolating valves for the regulators.
  • Friday, September 29, 2017 11:53 AM
    Reply # 5287683 on 5285431

    NFPA 2015 Pressure indicators and manometers for medical gas piping systems shall be cleaned for oxygen service. Gauges shall comply with ANSI!ASME B40.100,

    Pressure Gauges and Gauge Attachments.* The scale range of positive pressure analog indicators shall be such that the normal operating pressure is within the middle third of the total range [e.g., an indicator of 0 to 2070 kPa (0 to 300 psi) would have a lower third of 0 to 690 kPa (0 to 100 psig), a middle third of 690 kPa to 1380 kPa (100 psig to 200 psig), and a top third of 1380 kPa to 2070 kPa (200 psig to 300 psig)]. The accuracy of digital indicators shall be ±5 per- cent of the operating pressure at which they are used. The scale range of vacuum indicators shall be 0 to 760 mm (0 to 30 in.) gauge HgY. Indicators with a normal range display shall indicate normal only above 300 mm (12 in.) gauge HgY. 

  • Monday, October 02, 2017 5:57 PM
    Reply # 5291620 on 5285431

    I might chime in here. I should be addressing this in the MGPHO meeting this week. We never required source valves in category 3 until the 2015 version, making it now a requirement to place downstream pressure switches downsteam of any emergency shutoff valves. Since no dental company actually manufacturers these downstream pressure switches except in the zone valves (emergency shutoff valves) this now requires a zone valve be installed on any system with source shutoff valves.

  • Tuesday, October 03, 2017 7:35 AM
    Reply # 5292412 on 5285431

    Please do!

  • Monday, October 09, 2017 7:32 AM
    Reply # 5303292 on 5285431
    Al Moon (Administrator)

    Another great talk from Daniel Shoemaker at the 16th annual MGPHO meeting.


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