Hoses and Piping Under Pressure
Hoses and pipes under pressure are very hazardous and care must be taken when working with them. It's important to understand how pressure is measured.
Keep pressure gauges calibrated.
- Gauges on platforms are usually calibrated to read zero pressure at sea level.
- Gauges measure pressure in pounds per square inch gauge (psig)- the force in pounds of pressure per square inch on a surface relative to atmospheric pressure.
- When you read 40 psig on a gauge, the actual or "absolute" pressure (psia) which is the pressure relative to a zero-pressure environment (outer space) would be 14.7 psi greater or 54.7 psia.
When using temporary hoses and piping under pressure, ensure the following:
- Secure temporary hose, piping, and/or associated connections operating under pressure. This will help prevent workers from falling or moving objects while disconnecting.
- All temporary hoses, piping, and/or associated connections operating at a working pressure of 290 psig or more should be designed and used according to manufacturer specifications or certified by a professional engineer.
- Establish a safe work zone and post warning signs before temporary hoses and piping are pressurized to 290 psig or more.
- No workers should enter a danger zone while hoses or piping are under pressure unless allowed to do so by a supervisor or authorized representative.
Knowledge Check Choose the best answer for the question.
2-4. What should be done before temporary hoses and piping are pressurized to 290 psig or more?
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