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Applegarth30101  
#1 Posted : 17 May 2021 14:31:29(UTC)
Rank: Forum user
Applegarth30101

Flat fan spray nozzles: the amount and uniformity of the spray solution should be checked by making sure the mass of deionised water from both nozzles is 1g ± 0.02g at 0.1s and 30psi and/or 5.4g ± 0.06g at 1s and 30 psi during a dry run of the test for at least 10 cycles.

Electronic pressure regulator within control panel: pressure value displayed on regulator should correspond to input pressure on the external display of control panel – range: 0 psi to 50 psi – check in increments of 10psi. The pressure gauges must read within  ± 0.4psi tolerance?

Pressure gauge on pressure vessel: check ability to control pressure from 0 to 60 psi – this can in turn inform about any fault with electronic pressure regulator and air filter regulator. Working pressure is 30psi ± 2psi (approximately 0.2 MPa as per unit on current gauge).

paul.skyrme  
#2 Posted : 17 May 2021 18:21:07(UTC)
Rank: Super forum user
paul.skyrme

Not quite enough information, but, from what you have put, I can’t see how.

The system cannot become pressurised to dangerous levels if it is open ended and just carrying water.

Though to give a full answer, much more info would be needed.

Ian Bell2  
#3 Posted : 17 May 2021 19:22:45(UTC)
Rank: Super forum user
Ian Bell2

As Paul says, there isn't enough information to answer the question. Most of the data values you provide is/are irrelevant to PSSR.

The broad rules are, PSSR apply to any system containing steam, regardless of temperature and pressure. From the information you have given (no temperature information) then the quantities are very small I doubt if there is any steam at the operating pressure you have quoted?

You have quoted a complete mix of units of measure mixing Imperial with SI (pressure in psi, mass in grams) - this is poor technical practice. Like it or not, modern engineering works to the SI system. Pressure is measured in Pascals, Pa. However the reality is you need to convert between units Bar, Pascals, psi.

PSSR applies to systems of 0.5 bar or greater (7.25psi in old money) or 50000 Pascals above atmospheric pressure. However if the system capacity is less than 250bar litres (yet another type of unit, unique, I think (??) to the PSSR).

What does this mean? You have quoted a system operating pressure of  2.07bar (30psi) so if the internal volume (in litres) of any pressure vessel in your system is greater than approximately 121 litres then PSSR will apply. If less than 121 litres volume then PSSR won't apply.

So you need to measure/work out the internal volume of any vessels subject to the 2.07bar operating pressure. If you don't have this already written down, remember when taking the vessel measurements you will have to convert to litres  (1m^3 = 1000litres). Otherwise can you fill up your vessel with water and measure the volume of water in litres?

For more info refer to HSE ACOP L122

Ian Bell2  
#4 Posted : 17 May 2021 19:27:01(UTC)
Rank: Super forum user
Ian Bell2

Sorry, forgot to add - as Paul says, if this is an 'open' system then the pressure cannot rise.

Is the 2bar pressure the discharge pressure from the spray nozzle? Is this the same as the pressure inside the pressure vessel that is mentioned?

Clarification of you process would be helpful

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