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  • Users: DavidCR
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  1. DavidCR

    Custom o-ring 2m (78inch) flange flattness

    Hello and blessings to all. I need to specify the flange face flatness manufacturing tolerances for a flange with rubber o-ring seal. The flange is for a 2m diameter pipe custom design for cold water. I have the o-ring groove design and required finishes, but noy sure how to specify the...
  2. DavidCR

    Distance from AST diesel tank to power transmission line

    Hello dear everybody. Can somebody help me to find info or give hints on what security distances should be considered from a fuel oil #2 tank AST atmospheric fixed roof tank (28m diameter) from a power transmission line. (No problem, if not in USA, any country guidance would be appreciated).
  3. DavidCR

    Fire hydrants used for non fire operations

    Hello. In a power plant with water fire system fed by gravity tank (no fire pump). The hydrants are also used for washing operations mainly washing down cooling towers (they need a good stream to remove algae, mineral deposits, etc.), fire system is great for this. Water source is reliable and...
  4. DavidCR

    RT4 for hydrogen?

    I saw a pressure vessel used to conserve hydrogen (generated by a small electrolysis h2 generator) for an industrial process (to supply H2 for a H2 cooled generator in power plant). The U plate says MAWP 300psi@200F/ MDMT300psi@-20F, "FOR HYDROGEN" and RT4. The operation pressure is much lower...
  5. DavidCR

    Confiscated car lot fire protection

    Hello. Does somebody know how to protect, refer to a NFPA or other standard, or give hints about fire protection for: - Confiscated car and motorcycle parking lot. - Open area, 10000m2 (100x100m, 330x330ft). - Paved ground surrounded by concrete block wall. - Rural area - Some cars may be in...
  6. DavidCR

    Why fire SLC alarm cable shall not be shielded? Aply same for NAC?

    Blessings, and a hello to everybody. I've seen in wiring manuals, and cabling guides, from fire alarm panels of main manufacturers (Notifier for example) that SLC fire cable for inteligent panels should not be shielded, and if shielded, the shield shall be broken or isolated from devices ground...
  7. DavidCR

    Why fire SLC alarm cable shall not be shielded? Aply same for NAC?

    Blessings, and a hello to everybody. I've seen in wiring manuals, and cabling guides, from fire alarm panels of main manufacturers (Notifier for example) that SLC fire cable for inteligent panels should not be shielded, and if shielded, the shield shall be broken or isolated from devices ground...
  8. DavidCR

    Best material for HVAC chilled water pipes

    Hi everybody. What is the best material for chilled water pipes for HVAC systems thinking of long term leak free life?. Thanks in advance.
  9. DavidCR

    Alarm: SLC and NAC circuits in the same raceway?

    Hi to everybody. Is it possible under the NFPA 72 to have different circuits in same raceways?... Please see included sketch. 1. NAC and SLC in the same receway (EMT for example)? 2. Two different SLCs in the same raceway.? 3. Two different NACs in the same raceway? Supossed class A go and...
  10. DavidCR

    Smoke detector spacing with low height ceiling and beams.

    Hello. A question on smoke detector spacing/location. Case: Intermediate floor with low ceiling. Ceiling height: H=2m (6.7´) Beam height: h=0.38m (15") Beam distance: L=1m (3.3´) For smoke detectors: since h>0.1H, and L>0.4*H >them each beam space is a pocket so I need a @#%& lot of...
  11. DavidCR

    Extra security for deluge valve

    We are thinlking on using a deluge system indoors where preventing water damage is very important issue for the client, and we are thinking on using a deluge system. I have worked with common deluge valves (Viking, Tyco), for many industrial or common applications where following the normal...
  12. DavidCR

    Theater stage proscenium opening fire protection on NFPA101

    Hi everybody. Case: existing theater stage proscenium opening. Prescriptive protection. NFPA 101 includes requirements for theaters and specific requierements for the proscenium opening (front of stage in front of the audience) to prevent a fire on the stage to affect the audience. For new...
  13. DavidCR

    Aspirating smoke detector on battery rooms are XP?

    Hello everybody. Our company generalises that battery lead type semi-closed (that may produce H2) rooms shall include explosion proof devices and so explosion proof smoke detectors. I want to know if I use an aspirationg smoke detector like (Vesda or other) installed outside the battery room...
  14. DavidCR

    Smoke detector on hydropower big main hall.

    Hi everybody. In an hydroelectric power house with a main hall of 76m(250') long, 20m(66')wide, 18m(60') high we want to know if smoke detector can be omited on this space. All other floors bellow grade level and all equipment has propper fire detection. We have considered all the...
  15. DavidCR

    Air vacuum relief calculations for hydro penstock

    Hi. We have a 2.9m (114.2") hydroelectric penstock that we are refurbishing. The original design included 4 air vacuum/releif valves with a flanged connection of 300mm (12"). The valves are very old (italian brand) and we cannot find tecnical info about them and we want to know the design...
  16. DavidCR

    Fire pump, PRV piped back to suction

    Please see the diesel pump installation in the attached drawing. Due to site limitations, the suction tank is above and not beside the pump house. The hydrants and sprinklers are pretty far and in a lower location. A pressure relief valve is needed to protect the accessories of the system...
  17. DavidCR

    Operating testing of deluge system indoors

    Hi guys. In a power plant there is an old deluge system with open spray nozzles that protects a lub oil tank, pipes and pumps inside the power house building. We need to refurbish this system that has some defective components. The systems consists of a Viking E deluge valve, with electrical...
  18. DavidCR

    One relief valve for two diesel twin pumps

    Hi everybody. In an installation of two twin diesel centrifugal split case pumps, one as main and the other as back up. Both take water from the same suction tank and both supply water to the same fire water system. In case we need a relief valve to protect the system from overpressure. We...
  19. DavidCR

    Jockey pump with hydroneumatic tank

    We have a hydrant system with most pipes exposed on a power plant with a regular jockey pump. We think the size of the jockey pump is fine (15gpm-3hp). We have met problems setting the on-off values of the jockey pump (goes on&off very often), and with the fire pump start setting. Maybe due to...
  20. DavidCR

    is this the rigth forum? (valve turbulence problem)

    We have a hydro power pipe where the spherical ball when closing is inducing strong vibrations downstream. Is this the right forum to make such a question?. Or would you please recommend other?, which one?

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