PVF Reference Library · Technical Reference
Cast Iron Soil Pipe (No-Hub and Hub-and-Spigot)
Cast iron soil pipe is used for drain, waste and vent systems, and it comes in no-hub and hub-and-spigot styles with their own joining systems. This sheet covers how to tell them apart, the coupling and gasket types and what to confirm before ordering.
Draft, open for review. Check every value against the governing standard and the manufacturer’s data before use.
What it is
Cast iron soil pipe and fittings carry sanitary waste, storm drainage and vents, mostly in commercial and multi-story buildings. It is quiet and noncombustible. No-hub pipe has plain ends and is made to ASTM A888 and CISPI 301. Lengths are joined with no-hub couplings: a neoprene sleeve gasket clamped by a stainless steel shield and bands. Hub-and-spigot pipe has a bell (hub) on one end and is made to ASTM A74. It is joined with a compression gasket or the older lead and oakum method. Hub-and-spigot comes in Service (SV) and Extra Heavy (XH) weights.
How to identify
No-hub pipe has the same outside diameter end to end, with no bell. Hub-and-spigot pipe has a bell on one end. Both are marked with the maker, size, standard and country of origin. Look for the CISPI or listing mark on pipe and couplings when the job requires it.
Joint and coupling types
| Type | Used with | How it seals | Notes |
|---|---|---|---|
| Standard no-hub coupling | No-hub pipe and fittings | Neoprene sleeve under a stainless shield | Made to CISPI 310 |
| Heavy-duty no-hub coupling | No-hub pipe, where specified | Neoprene sleeve under a heavier shield and more bands | Specified for some jobs and sizes; check the spec |
| Compression gasket | Hub-and-spigot | Gasket in the hub, spigot pushed in | Gasket made to ASTM C564 |
| Lead and oakum | Hub-and-spigot | Packed oakum and poured lead | Mostly repair of older systems |
| Transition coupling | Cast iron to plastic or other pipe | Sized sleeve for each OD | Must be listed for the two materials |
Key points
- Confirm the style before ordering. No-hub couplings will not fit hub-and-spigot pipe ends without the right transition.
- SV and XH hub-and-spigot pipe have different outside diameters. Gaskets are made for one or the other.
- Coupling band tightening values come from the coupling maker and CISPI 310. Use a preset torque wrench made for no-hub bands.
- No-hub systems need hangers and bracing per the plumbing code and the CISPI installation handbook.
- Local codes may limit which joints are allowed below ground or under slabs.
Common mistakes
- Ordering SV gaskets for XH pipe.
- Using standard couplings where the spec calls for heavy-duty.
- Joining plastic to cast iron with a coupling not listed for the transition.
- Overtightening bands with an ordinary ratchet.
Governing standards: ASTM A888 and CISPI 301 (no-hub pipe and fittings); ASTM A74 (hub-and-spigot pipe and fittings); CISPI 310 (no-hub couplings); ASTM C564 (rubber gaskets). Local plumbing code.
Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.
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