WS/SS Rising main design requirment 1

[SAO2021]

I am new to rising main design and any expert would help with my question, really appreciate here
1. is there a requirement for putting inspection chamber at certain distances for maintenance like say every 100m?
2. is air valve at every high point and scour valve at every low point a must? both for water supply rising main and wastewater rising main, maybe the watersupply rising main doesn't need the scour valve at low point?
3. is there a maximum pipe deflection? less than 45 degree is acceptable? Need concrete thrust block at each turning point?
4. Anything major to look out during the design?
My working experience is all gravity sw/ss pipes and not too sure about the rising main so i think it's the best place to ask here

 

[bimr]

I am new to rising main design and any expert would help with my question, really appreciate here
1. is there a requirement for putting inspection chamber at certain distances for maintenance like say every 100m?
2. is air valve at every high point and scour valve at every low point a must? both for water supply rising main and wastewater rising main, maybe the watersupply rising main doesn't need the scour valve at low point?
3. is there a maximum pipe deflection? less than 45 degree is acceptable? Need concrete thrust block at each turning point?
4. Anything major to look out during the design?

1. No
2. This will need to be evaluated. Air valves should generally be avoided on wastewater forcemains as the air valves will foul and leak. The fluid velocity is very important since the fluid can be used to push the air downstream. Pipe strength is also an issue if there will be possibility of vacuum.
3. There is no maximum pipe deflection. Avoid thrust blocks by using mechanically restrained joints.
4. Yes, have a mentor review the design. Review for possible water hammer and pump failure modes.

 

[HTURKAK]

I agree with bimr (Civil/Environmental) but with some differences..

1- Inspection chamber or inspection manhole is used for gravity lines ..For waste water and potable water risings no..

2- This is the basic principle .. provide air valve chamber at high points and wash out/ drain chamber at low points.. But, IMO, the best practice for waste water risings, avoid the use of AV and Wash out Valve. Try to reach the highest point without AV and WO C and go with gravity flow after..The local codes may differ..

3- Provide Thrust blocks for bends, end caps, tees etc. shall be provided for all pipes which has not tension resistant joints .

 

[FacEngrPE]

If air vents are unavoidable, it is best to install them so any liquid leakage from the air vent is routed to a sanitary collection system.
I have seen one of these air vents stick wide open, so maximum stuck open flow rate is now my criteria for a sanitary sewer vent leakage capture.