How it connects
Joined using PVC primer and solvent cement (ASTM D2564). The fitting's ID solvent-welds over 3" Sch 40 pipe (3.5" OD), or its OD solvent-welds inside 4" Sch 40 pipe (approx. 4.0" ID).
Male and female halves
Dual-gender combo end: acts as a female socket (hub) when mating over 3" pipe, or as a male spigot when mating inside 4" pipe.
Usually connects to
- 3-inch Schedule 40 PVC DWV pipe (outside)
- 4-inch Schedule 40 PVC DWV pipe (inside)
Common sizes
- Nominal 3 in. x 4 in. DWV (3" socket ID ~3.5 in., 4" spigot OD ~4.0 in. to fit Sch 40 PVC DWV pipe)
Where it is used
residential plumbingcommercial plumbingDWV drainage systemstoilet closet flange installations
Variations
- straight closet flanges
- offset closet flanges
- closet flanges with knockout test caps
- closet flanges with stainless steel or plastic swivel rings
How to recognise it
A cylindrical barrel on closet flanges whose internal diameter forms a standard socket hub sized to slip over 3-inch pipe (~3.5" ID), while its outer diameter is sized (~4.0" OD) to slip directly into 4-inch Schedule 40 pipe.
Often confused with
| Confused with | How to tell them apart |
|---|---|
| Standard 3" DWV socket | A standard 3" socket does not have an outer barrel diameter machined or molded to fit inside 4" pipe. |
| Standard 4" DWV socket | A standard 4" socket fits over the outside of a 4" pipe (4.5" ID socket), whereas this fitting barrel inserts inside the 4" pipe. |
Also called
3x4 closet flange connection3" or 4" dual fit solvent weld hubfits over 3" or inside 4" DWV joint3x4 dual-fit combo socket/spigot
Good to know
Commonly encountered on 3x4 toilet closet flanges (including offset flanges) to allow a single fitting SKU to adapt to either 3" or 4" rough-in drainage piping.
Design with real parts
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