Instrument Air

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  • Wednesday, April 18, 2018 3:51 PM
    Message # 6109711
    Deleted user

    Instrument Air is a support gas with a standard pressure is 160-185 psig.  System labeling must include whatever the normal pressure is if different than the designated standard pressure.  (i.e. outlets, zone valves, all other shut offs, piping must include "x psig")


    NFPA 99, 2018  

    5.1.13.3.4.5 Instrument air compressors shall be permitted to be of any type capable of the output pressure needed for the intended line pressure see Table 5.1.11, and of providing air meeting the definition of instrument air in 5.1.13.3.4.1.




  • Thursday, April 19, 2018 6:45 AM
    Reply # 6110412 on 6109711
    Deleted user

    If you call the system "instrument air" and the system pressure is below 160 psi do all outlets, valves, & piping have to include the system pressure?

  • Thursday, April 19, 2018 6:47 AM
    Reply # 6110415 on 6109711
    Deleted user

    Can you use non-instrument air (such as a filtered, dry, 60 psi compressed air system) for boom brakes and avoid the requirement for zone valves & area alarms?

  • Thursday, April 19, 2018 7:50 AM
    Reply # 6110473 on 6110412
    Cary Darden (Administrator)
    Steve Bradshaw wrote:

    If you call the system "instrument air" and the system pressure is below 160 psi do all outlets, valves, & piping have to include the system pressure?

    NFPA 99-2018

    5.1.11.3.2 Where medical gas systems operate at pressures

    other than the standard gauge pressure of 345 kPa to 380 kPa

    (50 psi to 55 psi) or a gauge pressure of 1100 kPa to 1275 kPa

    (160 psi to 185 psi) for nitrogen, the station outlet identification

    shall include the nonstandard operating pressure in addition

    to the name of the gas.


    The code only mentions nitrogen, the intent is probably that instrument air also be included here, it should probably say "for medical support gases"


  • Thursday, April 19, 2018 7:58 AM
    Reply # 6110480 on 6110415
    Cary Darden (Administrator)
    Steve Bradshaw wrote:

    Can you use non-instrument air (such as a filtered, dry, 60 psi compressed air system) for boom brakes and avoid the requirement for zone valves & area alarms?


    5.1.6.11 The installation of manufactured assemblies shall be

    tested in accordance with 5.1.12


    I can't think of anything in 5.1.12 that specifically would prohibit this, and as long as the manufacturer instructions do not specifically say "Nitrogen or Instrument Air per NFPA 99" or something like that it would be fine


  • Thursday, April 19, 2018 1:12 PM
    Reply # 6111199 on 6109711
    Deleted user

    Thanks Cary and good catch - I agree with you about the intent.

    5.1.11.2.2 did include both nitrogen & instrument air


    If the equipment manufacturer doesn't specify, what can control air (non-instrument air) not be used for?

  • Friday, April 20, 2018 8:57 AM
    Reply # 6112455 on 6111199
    Cary Darden (Administrator)
    Steve Bradshaw wrote:


    If the equipment manufacturer doesn't specify, what can control air (non-instrument air) not be used for?


    If we are using NFPA 99 as a guide I would say control air / non-instrument air can be used for anything that doesn't fall under the umbrella of medical support gas or medical air.


    Having said that I might need to walk back what I previously wrote regarding what type of air sources can drive booms.  Under the definition for "Medical Support Gas" one of the examples they list are air-driven booms.  That gives weight to the argument that booms should be driven by nitrogen or instrument air as per NFPA 99.  


    NFPA 99-2018

    3.3.107 Medical Support Gas. Nitrogen or instrument air

    used for any medical support purpose (e.g., to remove excess

    moisture from instruments before further processing, or to

    operate medical–surgical tools, air-driven booms, pendants, or

    similar applications) and, if appropriate to the procedures,

    used in laboratories and are not respired as part of any treatment.

    Medical support gas falls under the general requirements

    for medical gases. (PIP)


    3.3.102* Medical Air. For purposes of this code, medical air is

    air supplied from cylinders, bulk containers, or medical air

    compressors or reconstituted from oxygen USP and oil-free,

    dry nitrogen NF. (PIP)


  • Friday, April 20, 2018 9:26 AM
    Reply # 6112514 on 6109711

    This sounds like a job for non-medical air!   Be sure to put up some diagonally striped pipe labels too. 

     

    NFPA 99, 2018 

    8.3.5 Nonmedical Compressed Air.

    8.3.5.1 Nonmedical air compressors shall be listed or approved.

    8.3.5.2 Nonmedical compressed air shall not be used for powering medical instruments or for human respiration.

    8.3.5.3 Nonmedical compressed air shall meet the quality and pressure requirements of the equipment connected to the system.

     

    It may be more simple to use the support gas for brake booms, but this would be an option if the facility does not have piped Nitrogen or Instrument Air.

  • Friday, April 20, 2018 10:18 AM
    Reply # 6112566 on 6109711
    Cary Darden (Administrator)

    Steve, one more thing:


    The term "shall" is used when the language is mandatory.  So 5.1.13.1.2 says "shall be permitted" so I'm just going to say I don't know, people should just do whatever makes them happy with regards to boom brakes.  


    I would only use brakes that are driven by electricity because finding nitrogen leaks often involves a stupid amount of effort to meet 5.1.14.2.3.2 requirement.  It just so happens that I don't have any plans to purchase any booms in the near future so my opinion on the matter is pretty useless


    5.1.13.1.2 Support gas sources shall be permitted to be used

    for many general utility uses (e.g., to remove excess moisture

    from instruments before further processing, or to operate gasdriven

    booms, boom brakes, pendants, or similar applications).

    (See Chapter 8 for general utility systems requirements.)


  • Friday, April 20, 2018 10:19 AM
    Reply # 6112567 on 6112514
    Cary Darden (Administrator)
    Corky Bishop wrote:

    This sounds like a job for non-medical air!   Be sure to put up some diagonally striped pipe labels too. 

     

    NFPA 99, 2018 

    8.3.5 Nonmedical Compressed Air.

    8.3.5.1 Nonmedical air compressors shall be listed or approved.

    8.3.5.2 Nonmedical compressed air shall not be used for powering medical instruments or for human respiration.

    8.3.5.3 Nonmedical compressed air shall meet the quality and pressure requirements of the equipment connected to the system.

     

    It may be more simple to use the support gas for brake booms, but this would be an option if the facility does not have piped Nitrogen or Instrument Air.


    Corky, is a boom considered to be a "medical instrument"?  


    I would think this primarily refers to tools that are typically driven by support gases such as saws, drills, etc. but I wasn't sure if booms might be interpreted as being a medical instrument.



    Last modified: Friday, April 20, 2018 10:52 AM | Cary Darden (Administrator)
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