NFPA 99 and ISO 7396-1 Valve configuration

  • Wednesday, August 12, 2020 7:12 PM
    Message # 9161588

    Yesterday I received from an ASSE 6010 Installer a query from Costa Rica, he comments that there is a manufacturer offering valves with straight threads as permitted in ISO 7396-1, and the distributor/manufacturer sent him a technical sheet in which he says that that configuration complies with NFPA99, it seems to me that no valve for medical gas piping with a configuration that includes straight threads complies with what is specified in NFPA99.

    Do you know about this or similar cases? What do you think of this particular issue?
    I am very worried about this situation!! 

    3 files
  • Thursday, August 13, 2020 8:03 AM
    Reply # 9162401 on 9161588

    These valves are absolutely and unequivocally NFPA compliant. The fittings used for these valves are not a threaded fitting where the seal is made by applying thread sealant to the threads. These are Zero clearance fittings where the seal is created on the face of the fitting. This allows for serviceability in the same way a standard three piece ball valve would. 


    • See Picture of the Zero Clearance  Valve                              
    • See Picture of the Standard Three Piece Valve

    2018 NFPA Valve Types. New or replacement valves shall be permitted to be any type as long as they meet the following conditions:

    (1) They have a minimum Cv factor in accordance with either Table (a) or Table (b).

    (2) They use a quarter turn to off.

    (3) They are constructed of materials suitable for the service.

    2012 NFPA Valve Types. New or replacement valves shall be as follows:

    (1) They shall be of the quarter turn, full ported, ball type.

    (2) They shall be of brass or bronze construction.

    (3) They shall have extensions for brazing.

    (4) They shall have a handle indicating open or closed.

    (5) They shall consist of three pieces permitting in-line serviceability. Threaded Fittings. Threaded fittings shall meet the following criteria:

    (1) They shall be limited to connections for pressure and vacuum indicators, alarm devices, check valves, and source equipment on the source side of the source valve.

    (2) They shall be tapered pipe threads complying with ASME B1.20.1, Pipe threads, general purpose, inch.

    (3) They shall be made up with polytetrafluroethelyne tape or other thread sealant recommended for oxygen service, with sealant applied to the male threads only and care taken to ensure sealant does no enter the pipe. 


    2 files
    Last modified: Thursday, August 13, 2020 8:14 AM | Anonymous
  • Thursday, August 13, 2020 11:36 AM
    Reply # 9162846 on 9161588

    The zone valve boxes are from Beacon Medaes and Mark can chime in and give more information. These valves have been used in Asia for quite a while.

  • Thursday, August 13, 2020 12:32 PM
    Reply # 9162953 on 9161588

    I started looking at the spec sheet on this when I saw just how much this was a space saving (and time saving) design. Just wondering how common is it to find a mfg. supplied component with tubing (type K-per mfg. specs) bent in that fashion outside of a manifold or other source equipment? 

    Also, (for my education), on what grounds can the manufacturer of a zone valve decide to bend the tubing and state that it complies with NFPA requirements?  (Product is listed on "NFPA Products" section of their website.)

    Trust me, I am not trying to stir something up here. I think that this is a wonderful design that others will emulate. I am just curious...

    Bob W.

  • Friday, August 14, 2020 6:16 AM
    Reply # 9164160 on 9161588

    Robert - this is a common misapprehension when people look at this design, and unless you are into tubing manufacturing the distinction is not always clear.  The tubes are not bent, they are formed.  Bending runs the risk of thinning the outer parts of the tube, "corrugating" the inside curve, etc, etc.  Thus NFPA has always been leery of bending.  You could never bend a curve this tight.

    Forming is the process that would be used to make an elbow fitting.  Because it is done in the factory under controlled conditions, the final result is essentially no different from a length of straight tubing.  Thicknesses are kept uniform, strength is preserved (Beacon did the full hydrostatic testing on the product to prove it - we were concerned too) and of course the final result can be cleaned as would be necessary for any length of tubing.  

    It is an example of why the manufactured assembly rules are there - you can do things safely in a factory under controlled conditions that would be very problematic in the field. 

  • Friday, August 14, 2020 9:53 AM
    Reply # 9164485 on 9162401
    Jay D'Agostino escribió:

    Estas válvulas cumplen absoluta e inequívocamente con la NFPA. Los accesorios usados ​​para estas válvulas no son un accesorio roscado donde el sello se hace aplicando sellador de roscas a las roscas. Estos son accesorios de espacio libre cero donde el sello se crea en la cara del accesorio. Esto permite la facilidad de servicio de la misma manera que lo haría una válvula de bola estándar de tres piezas. 


    • Ver imagen de la válvula de espacio libre cero                              
    • Ver imagen de la válvula estándar de tres piezas

    2018 NFPA Tipos de válvulas. Se permitirá que las válvulas nuevas o de reemplazo sean de cualquier tipo siempre que cumplan las siguientes condiciones:

    (1) Tienen un factor Cv mínimo de acuerdo con la Tabla (a) o la Tabla (b).

    (2) Usan un cuarto de vuelta para apagarse.

    (3) Están construidos con materiales adecuados para el servicio.

    2012 NFPA Tipos de válvulas. Las válvulas nuevas o de reemplazo serán las siguientes:

    (1) Deberán ser del tipo bola, de cuarto de vuelta, con puerto completo.

    (2) Serán de latón o bronce.

    (3) Deberán tener extensiones para soldadura fuerte.

    (4) Deberán tener una manija que indique abierto o cerrado.

    (5) Deberán constar de tres piezas que faciliten la capacidad de servicio en línea. Accesorios roscados. Los accesorios roscados deben cumplir los siguientes criterios:

    (1) Deberán limitarse a conexiones para indicadores de presión y vacío, dispositivos de alarma, válvulas de retención y equipo fuente en el lado de la fuente de la válvula fuente.

    (2) Deben ser roscas de tubería cónicas que cumplan con ASME B1.20.1, Roscas de tubería, uso general, pulgadas.

    (3) Deben estar hechos con cinta de politetrafluoroetileno u otro sellador de roscas recomendado para servicio de oxígeno, con sellador aplicado solo a las roscas macho y se debe tener cuidado para asegurar que el sellador no entre en la tubería. 


    Hola Jay, thank you for the detail show in your comment, my principal concern is that Beacon shows this model on the web page as a design under ISO standard, and I did not have that detail you showed that is very relevant to see the performance and configuration of the valves. Additionally I was concern about the code prohibition of straight thread and the union type connection that are prohibited in the code, I already talk with Mark and he Clear me up about this detail.
  • Friday, August 14, 2020 11:14 AM
    Reply # 9164762 on 9161588

    Thanks, Mark for the info on the tubing. I was clearly incorrect using the word “bent” (and you set me straight).

    Bob W

  • Monday, August 17, 2020 6:35 AM
    Reply # 9169564 on 9164762
    Robert Woisard wrote:

    Thanks, Mark for the info on the tubing. I was clearly incorrect using the word “bent” (and you set me straight).

    Bob W


    In addition to Mark's comments and clarifications I wanted to also point out that 5.1.10 Category 1 Distribution, & refer specifically to field-installed piping, which this is not. As Mark stated, these are manufactured in a controlled environment which allows us to maintain a much higher and consistent quality than you would in the field. This is precisely why it states Field-Installed. 

  • Tuesday, August 18, 2020 6:10 AM
    Reply # 9172292 on 9161588
    Deleted user

    Very innovative - should really help in keeping the wall space narrow and I like that the valves are all the same level.  The curved tubing is really akin to a fitting.

    Hospitals can now avoid firing the short nurse simply because she can't reach to top valve

  • Friday, August 21, 2020 5:19 AM
    Reply # 9181147 on 9172292
    Steve Bradshaw wrote:

    Very innovative - should really help in keeping the wall space narrow and I like that the valves are all the same level.  The curved tubing is really akin to a fitting.

    Hospitals can now avoid firing the short nurse simply because she can't reach to top valve

    Great point Steve. 

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