# Pressure testing suction pipes  

In my company we commonly pressure test pipes to the following standards:  

## Pressure pipelines  

* Buried pipes except PE - BS EN 805  
* Buried PE - WIS-4-01-03  
* Above ground pipes - WIMES 8.08  

## Gravity sewers/drains  

* Code for adoption sections E7.4 and E7.5  
* BS EN 1610  

But none of the above standards address how to pressure test suction mains.  

From a little reading around the subject I tentatively suggest the following approach.  

The main issue with suction mains is to ensure air isn't drawn in through any leaky 
joints. It takes approximately 3 - 5 times less differential air pressure than water 
pressure for air to leak [see link](https://griswoldcontrols.com/project/pressure-testing-air-vs-water/#:~:text=To%20find%20leaks,%20a%20low%20pressure%20(30-50%20PSI),89%20times%20greater%20than%20the%20viscosity%20of%20air.).  

So I suggest selecting a water test pressure above atmospheric pressure of 5 times the 
anticipated negative suction. So for instance if anticipated minimum pressure is 
-0.2 barg  

Test pressure $= |-0.2| \times 5$ = 1 barg  

If the suction line remains above atmospheric then I'd suggest just doing a water test.