Quick numbers
for the yard.
Pipe volume, concrete, bag counts and flange torque, worked the way the field works them. Reference only: verify against your spec, your gasket and flange suppliers, and your engineer of record.
Pipe water volume
Inside diameter used: — in. Steel walls are nominal ASME B36.10 values; HDPE ID = OD − 2 × (OD ÷ DR) using IPS outside diameters. Water at 7.4805 gal per ft³. Weight of water: — lb.
Concrete in cylinders
Volume = π × (D ÷ 2)² × depth. 27 ft³ per cubic yard. Order to the waste-inclusive number; a short pour on a pier is expensive. Need bags instead of a truck? Use the bag calculator below with the net cubic yards.
Sakrete bags vs. cubic yards
Volume → bags
Bags → volume
Rule of thumb: one cubic yard is 45 bags at 80 lb or 60 bags at 60 lb. Yields are the manufacturer’s nominal values for concrete mix; check the bag, and round up.
Bolt torque: raised-face weld neck flanges
Carbon steel and stainless studs on ASME B16.5 raised-face flanges, Class 150 through 900. Bolt count and diameter are the B16.5 pattern for each size; torque is calculated from the stud’s tensile stress area at the target stress you pick.
| NPS | Bolts | Stud dia. | Stress area (in²) | Target stress (ksi) | Torque (ft·lb) | Torque (N·m) |
|---|
T = K × d × F ÷ 12, with F = target stress × tensile stress area (UNC to 1", 8-UN above). B7 yield taken as 105 ksi; B8 Class 2 yield by diameter: 100 ksi to 3/4", 80 ksi to 1", 65 ksi to 1-1/4", 50 ksi to 1-1/2", and 30 ksi (Class 1) above. Values are for spiral-wound or similar metallic gaskets; soft, PTFE and sheet gaskets usually need less, and the gasket maker’s figure governs. Tighten in a cross pattern in at least three rounds (30 / 60 / 100%), then a final rotational pass. Follow ASME B16.5 for the flange and ASME PCC-1 for assembly practice.
Bolt torque: HDPE flange adapters
Polyethylene flange adapters with metal lap-joint (backing) flanges, Class 150 and 300. Class 150 values are the Plastics Pipe Institute’s published figures from TN-38; Class 300 uses the same TN-38 method on the Class 300 bolt pattern.
| IPS size | Bolts | Bolt dia. | Initial min. (ft·lb) | Initial max. (ft·lb) | N·m (min–max) | Face OD / ID (in) |
|---|
TN-38 tightening procedure
- Clean and inspect flanges, bolts and nuts. Lubricate threads and the flange face under the nut.
- Hand-tighten, then pre-tighten all bolts in sequence to 10–20 ft·lb, never above 20% of target.
- 4 to 12 bolts: rounds at 30%, 60%, 100% of target. 16 or more bolts: 25%, 50%, 75%, 100%.
- Finish with a rotational (clockwise) pass at 100% until no nut turns further.
- Mandatory re-torque to the target value 4 to 24 hours later, after the HDPE creep-relaxes.
- Check the backing-ring gap around the circumference between rounds; correct any unevenness before continuing.
Criss-cross sequence by bolt count
| Bolts | Tightening order |
|---|---|
| 4 | 1-3-2-4 |
| 8 | 1-5-3-7 » 2-6-4-8 |
| 12 | 1-7-4-10 » 2-8-5-11 » 3-9-6-12 |
| 16 | 1-9-5-13 » 3-11-7-15 » 2-10-6-14 » 4-12-8-16 |
| 20 | 1-11-6-16 » 3-13-8-18 » 5-10-15-20 » 2-12-7-17 » 4-14-9-19 |
| 24 | 1-13-7-19 » 4-16-10-22 » 2-14-8-20 » 5-17-11-23 » 3-15-9-21 » 6-18-12-24 |
Number bolts clockwise from the 12 o’clock position. Source: PPI TN-38, Bolt Torque for Polyethylene Flanged Joints (2019), which references ASME PCC-1 for sequences.
Need it built, not just calculated?
Send us the scope. You’ll get a straight answer on schedule and price, usually within two business days.