Taking a flanged branch from a main run classically needs three parts: an olet welded to the run, a nipple on top and a flange at the end. Three parts, three welds. Combined fittings do the same job in one item.
Three parts, three approaches
| Fitting | What it is | Where it stands out |
|---|---|---|
| Nipoflange | A weld neck flange combined with a nipolet in one body | Small bore branches; instrument and drain lines |
| Weldoflange | A weld neck flange combined with a weldolet | Lines needing a butt weld branch |
| Flangeolet | A flanged olet seated directly on the run | Tight spaces; short branch length |
The advantage is the same in all three: fewer welds, shorter installation and fewer seams to inspect. Since every weld is a potential defect, that also improves reliability.
Where they are used
- Pressure and temperature measurement points
- Safety valve connections
- Drain and vent outlets
- Sampling lines
- Chemical dosing connections
Selection criteria
Three inputs decide: run size and schedule, branch size and pressure class, and the branch end connection (flanged, threaded or socket weld). Reinforcement also matters; olet type fittings are self reinforcing and do not need a separate pad.
When ordering
State run size and schedule, branch size, pressure class, face type, material grade and standard together. These items generally fall under MSS SP-97 and may be produced to order, so plan lead time early.
See our forged steel fittings page and send your list through the enquiry form.
FAQ
What is the difference between nipoflange and weldoflange?
A nipoflange carries nipolet geometry at the branch and suits small sizes, while a weldoflange serves butt weld branch connections.
Do these fittings need reinforcement?
Olet type fittings are self reinforcing, so a separate reinforcing pad is generally not required.
Are they available from stock?
Common size and class combinations may be, but most are produced to order.
Send us your material list; we reply with price and lead time the same day.
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