Air release valve inside pumping station manhole?

[cht13er]

Good day!

I've got a 50mm (2") sanitary forcemain that will have a high point anywhere between where I'm connecting and the sanitary pumping station (SPS) it's discharging into (approx. 60m or less than 200' between the two). I had a look at this fabulous catalogue that a eng-tips user posted on another thread:

http://www.gaindustries.com/products1/bulletins/airvalves/Air_Valve_Bulletin.pdf,

but my question is just: "do I need a seperate manhole"?

My thought is that the high point could be located just inside the SPS - the air/vacuum combination valves aren't that large - and folowing that there's a downwards sweep to direct flows to the bottom of the wet well. Do you see any issues with this setup?

Thanks in advance for your thoughts,
Chris

 

[bimr]

If you have an Air release valve, you need a manhole.

Unless you have extreme elevations differences that may collapse the pipe, you should consider closing off the air valve with a manual valve after the forcemain startup. The air release valve will not be needed after startup.

Most wastewater textbooks recommend NOT using combination air release valves on wastewater force mains. See the attached reprints.

If you still have concerns, you should review the numerous posts on this forum that deal with forcemain problems and air release valves.