Tesco Steel & Engineering forges nipolets — the olet family's one-piece answer to the valve take-off: outlet base and nipple forged as a single fitting, the base butt-welded to the run pipe and the 3½″ integral nipple finished plain (bevelled) for butt welding or with a male NPT thread to ASME B1.20.1. The assembly it replaces — outlet plus screwed or welded nipple — loses one weld and one leak path, at exactly the section where a cantilevered root valve's vibration loads bite hardest. Reinforcement is forged into the body per MSS SP-97, in NPS ½″ to 2″, XS and XXS bores matched to Schedule 80 and 160/XXS branches, in every material grade on this site: carbon steel, LTCS, the chrome-moly ladder, stainless, duplex, the nickel alloys and copper-nickel — the 90/10 C70600 production photographed below. Each piece is marked with size, schedule, grade and heat, certified to EN 10204 3.1/3.2. Dimension table in the datasheet below. ISO 9001:2015, made in Mumbai, India — exported to 50+ countries.
MSS SP-97 · NPT to ASME B1.20.1Nipple Outlet · Valve Take-OffOne Piece — One Weld FewerNPS ½″–2″ · XS / XXS3½″ Standard LengthPlain Bevel or Male NPT EndEN 10204 3.1 / 3.2 · ISO 9001:2015
90/10 Copper-Nickel C70600 — Nipolets (Rear) with Their Threadolet Siblings: One Enquiry, Both Fittings
What is a Nipolet?
The take-off in one piece. A nipolet (also written nipple outlet) is a forged, integrally reinforced one-piece branch outlet: the contoured base butt-welds to the run pipe, and the nipple is forged integrally with it — no outlet-plus-nipple assembly, no joint between them. The 3½″ (88.9 mm) nipple end comes plain (bevelled) for butt welding or with a male NPT thread to ASME B1.20.1; reinforcement is forged in per MSS SP-97. Its classic duty is the root-valve take-off, drain, vent and sample connection on headers and vessels. We forge them NPS ½″–2″, XS and XXS bores, in every grade from A105 to the nickel and copper-nickel alloys, marked per piece and certified to EN 10204 3.1/3.2.
Outlet fitting, pipe nipple — two heats, two certificates
One forging, one heat, one certificate
Branch joints
Nipple screwed or welded into the outlet, plus the valve joint
The valve joint only — the outlet-to-nipple joint no longer exists
Leak paths
Every joint is one
One fewer, permanently
Weakest section under vibration
The thread root or fillet weld at the point of highest bending stress
Forged metal, tapering into the reinforced base
Shop & NDT hours
Fit-up, welding and examination of the extra joint
Deleted with the joint
The 3½″ standard length is not arbitrary: it stands the root valve clear of the header and its insulation, leaves room for the wrench, and gives the welder working space at the base — one dimension, chosen by decades of field practice.
The joint between them never exists — no thread root or fillet weld at the section where a cantilevered valve's bending stress peaks, just forged continuity into the MSS SP-97 reinforced base.
Two Ends, One Question
Plain (bevelled) for the all-welded line, or male NPT to ASME B1.20.1 for the threaded root valve — TOE or POE on the requisition, the run-pipe end stays a butt-weld base either way.
Schedule-Matched Bores
XS matches Schedule 80 branches, XXS matches Schedule 160/XXS — the nipple's OD is the nominal size's, so matched walls meet the downstream weld exactly as the code prefers.
The 3½″ That Fits the Field
One standard length across all six sizes — valve clearance above the insulation, wrench room, welding access at the base; longer or shorter forged on request.
Specification Notes — Getting Nipolets Right
Three honest notes.Nipolets are schedule-designated, not class-designated: order XS or XXS to match the branch line's wall — a specification that writes 'Class 3000 nipolet' by habit gets one clarifying question from us, not a guess. The male thread is the mirror of the threadolet's female: a threaded nipolet mates with a threaded valve or coupling, not with another male thread — check which side of the joint your take-off drawing actually shows before ordering both fittings for the same branch. And one piece does not repeal fatigue: a heavy root valve on any 3½″ cantilever still deserves the bracing your small-bore piping specification calls for where vibration is real — the nipolet removes the weakest joint from the section; the gusset rules still apply.
How Our Nipolets Are Manufactured
1
Material — certified forgings in the ordered grade, heat treated as the grade demands — normalised LF2, N&T chrome-moly, solution-annealed stainless and duplex — furnace records retained; heat-number transfer at the first operation.
2
One-piece machining — base and nipple turned from the single forging to the MSS SP-97 profile: reinforced base, nipple OD to nominal size, bore to XS or XXS.
3
Saddle contour — the base machined to the run-pipe curvature stated on the order, ready for the root-gap fit-up.
4
End finishing — bevel for the plain-end version, or male NPT cut and plug-gauged to ASME B1.20.1 for the threaded version.
5
Testing & marking — PMI on alloy grades, MPI/DPT/UT to the ordered scope, then marking: size, schedule, grade, heat number.
6
Certification & packing — EN 10204 3.1 MTC (3.2 witnessed on request); threads and bevels protected, packed sea-worthy.
Where Nipolets Are Used
Wherever a header sprouts a valve: refinery and petrochemical units run their root valves, drains and vents off nipolets by the thousand; power stations use the plain-end version on all-welded steam circuits; offshore and marine systems order them in copper-nickel and duplex for seawater headers; and vibrating services — compressor stations, pump discharge manifolds — specify them by name for the forged continuity where assemblies fail. Production batches below:
One Forging, End to End — Male NPT Above, Contoured Base BelowA105 Carbon Steel Nipolets — a Production Batch off the LathesThreaded-End (TOE) Nipolets in Rows — NPT Cut and Gauged
Nipolet Dimensions — XS & XXS Quick Reference
A is the overall length from outlet base to nipple end — the standard 3½″ (88.9 mm) across every size; C is the bore through the nipple, and the nipple's outside diameter matches the nominal pipe size. Catalogue dimensions in inches, millimetres in brackets.
NPS (inch)
A — Length
C Bore — XS
C Bore — XXS
½
3½ (88.90)
15/16 (23.81)
9/16 (14.29)
¾
3½ (88.90)
1 3/16 (30.16)
3/4 (19.05)
1
3½ (88.90)
1 7/16 (36.51)
1 (25.40)
1¼
3½ (88.90)
1 3/4 (44.45)
1 5/16 (33.34)
1½
3½ (88.90)
2 (50.80)
1 1/2 (38.10)
2
3½ (88.90)
2 9/16 (65.09)
1 11/16 (42.86)
The nipple's outside diameter always matches the nominal pipe size — XS or XXS changes only the bore, so match the nipolet's schedule to the branch line's and the downstream weld meets matched walls. Download the datasheet (PDF) for the full table with the dimensional drawing and installation guidance — non-standard lengths are forged on request.
How to Specify & Order a Nipolet
Seven elements — the schedule and the end type are the two that define this fitting:
1
Run pipe size and schedule — e.g. 8″ Sch 40; the base is contoured to it.
2
Nipple size — ½″ to 2″.
3
Schedule — XS to match Schedule 80 branches, XXS for Schedule 160/XXS systems.
4
End type — plain (bevelled) for butt welding, or threaded male NPT to ASME B1.20.1; TOE/POE shorthand welcome.
5
Length — 3½″ standard; state a non-standard length where insulation or rack space demands it.
6
Material grade & certification — exactly as your specification writes it, with EN 10204 3.1 (our standard) / 3.2 witnessed; MPI, DPT, UT or NACE scope if extended.
Example: “Nipolet, ¾″ × 3½″ long, XS, threaded one end NPT per ASME B1.20.1, on 6″ Sch 40 run, ASTM A105, B31.3, EN 10204 3.1 — 50 pieces.” Quotations normally within 24 hours with price, unit weights and delivery.
Nipolets — Frequently Asked Questions
What is a nipolet (nipple outlet)?
A nipolet is a forged, integrally reinforced one-piece branch outlet that combines two components in a single fitting: the contoured outlet base that butt-welds to the run pipe, and the nipple that would otherwise be screwed or welded into it. The body and its reinforcement follow MSS SP-97 like the rest of the olet family, but where a weldolet or threadolet ends at the outlet face, the nipolet keeps going — a 3½" nipple forged integrally with the base, finished either plain (bevelled) for butt welding or with a male NPT thread cut to ASME B1.20.1. Its natural duty is the valve take-off: header, nipolet, root valve, in one piece and one weld. We forge nipolets in NPS ½" to 2", XS and XXS bores, in every material grade on this site, each marked with size, schedule, grade and heat number and certified to EN 10204 3.1/3.2.
What does the nipolet replace — why one piece?
The classic small-bore take-off used to be an assembly: an outlet fitting welded to the header, plus a pipe nipple screwed or welded into it, plus the joint between them. The nipolet forges outlet and nipple as one, and that deletion is the whole argument. One weld disappears — the branch weld between outlet and nipple — taking its fit-up, its welder hours, its NDT and its inspection records with it. One leak path disappears with it: there is simply no joint between base and nipple to weep, back off or corrode. And one stress concentration disappears too, which matters more than it sounds, because the joint the nipolet eliminates sits exactly where a cantilevered valve's vibration loads are highest — the vibration question below tells that story. What is left is a single forging with a single butt weld to the header: fewer parts to buy, store and trace, and a shorter path from isometric to finished branch.
What standards cover nipolets?
The familiar division of labour. MSS SP-97 — Integrally Reinforced Forged Branch Outlet Fittings — owns the body: the forged-in reinforcement, pressure-temperature basis, marking and material cross-references, exactly as for the weldolet, sockolet and threadolet. ASME B1.20.1 owns the thread on the threaded version — here a male NPT taper on the nipple end, gauged like any pipe thread, made up hand-tight plus one and a half to three turns. On the line, branch reinforcement logic belongs to the piping code, B31.3 or B31.1, and the plain-end version's butt weld to the downstream pipe or valve follows the code's welding rules like any other butt joint. Materials certify to their own standards — A105, A350 LF2, A182, B564 — so the certificate reads like any forging certificate. One designation habit to note: nipolets are ordered by schedule, XS or XXS, not by the Class 3000/6000 numbers their threadolet and sockolet siblings carry — the sizing question explains why.
What sizes, bores and lengths do nipolets come in?
Deliberately few — the nipolet is a specialist. Sizes run NPS ½" through 2" (DN 15 to DN 50), because its duty is the small-bore take-off: valve connections, drains, vents, instrument and sample points. Two bores per size: XS, matching Schedule 80 branch systems, and XXS, matching Schedule 160 and XXS systems — the nipple's outside diameter matches the nominal pipe size, so the bore is what the schedule choice changes. One standard length: 3½" (88.9 mm) overall from outlet base to nipple end, across every size — chosen so a root valve and its wrench clear the header insulation and the welder has room to work; other lengths are forged on request. The datasheet tabulates all six sizes with both bores in inches and millimetres. State run pipe size and schedule with the order and the base comes contoured to the header it will sit on.
Plain end or threaded end — which do I order?
The nipple end comes two ways, and the downstream connection decides. Plain end: the nipple is bevelled and butt-welds directly to the mating pipe, valve or fitting of the same schedule — the all-welded choice for severe and cyclic service, hydrogen and high-temperature lines, anywhere the specification wants no threads in the pressure envelope. Threaded end: a male NPT taper to ASME B1.20.1, so a threaded root valve or fitting spins straight on — the habit of utility systems, drains, vents and gauge connections that live by make-and-break. Note which gender that is: the threadolet offers a female thread the branch pipe screws into; the nipolet's thread is male, standing ready for a valve or coupling — the two fittings answer opposite ends of the same joint. Ordering shorthand from the trade travels with this choice: TOE (threaded one end) and POE (plain one end) both appear on requisitions, and either way the run-pipe end stays a butt-weld base.
Why are nipolets designated XS and XXS instead of Class 3000 and 6000?
Because the nipolet is sized like the pipe it replaces, not like the fitting it resembles. A threadolet or sockolet is a socket for someone else's pipe, so it carries a fitting class — 3000 or 6000 — with the class-to-schedule mapping those pages explain. The nipolet is the pipe: its nipple runs in the line with the valve on its end, so it is specified the way pipe is specified, by wall — XS, whose bore matches a Schedule 80 branch, or XXS, whose bore matches Schedule 160 and XXS systems. The outside diameter is the nominal size's in both cases; only the bore changes. The practical rule at the isometric: match the nipolet's schedule to the branch line's schedule so bores align for flow and for welding — an XS nipolet butt-welded to Schedule 80 pipe presents matched walls to the weld, exactly as the code prefers. Where a specification does write 'Class 3000 nipolet' by habit, we read the branch schedule and confirm the wall before forging — the honest translation costs one question.
What materials are nipolets available in?
Every grade this site forges. Carbon steel A105 is the volume grade — the machined production batches photographed on this page are exactly that; low-temperature A350 LF2 covers the cold bench; chrome-moly A182 F11, F22, F5, F9 and F91 follow the alloy headers into steam and hydrogen service; stainless F304/304L and F316/316L with dual certification where heats qualify, plus stabilised F321 and F347; duplex F51 and super duplex F53/F55 for chloride duty; and the nickel and copper benches — Monel, Inconel, Incoloy, Hastelloy, and the copper-nickels: the golden pieces photographed here are 90/10 copper-nickel C70600, nipolets machined alongside their threadolet siblings for seawater service, where CuNi's biofouling resistance rules shipboard and offshore piping. Titanium against enquiry. Chemistry per heat, PMI on alloy grades, EN 10204 3.1/3.2 on every lot.
How is a nipolet installed?
One weld to the header, then whatever the nipple end asks. The branch location is marked on the run pipe and the opening cut; the contoured base is fitted with a root gap and joined with a full-penetration butt weld, exactly as on a weldolet — that is the fitting's only weld to the header. The plain-end version then butt-welds its nipple to the downstream pipe, valve or fitting of matching schedule, a standard butt joint under the code's rules. The threaded version needs its thread protected from spatter and heat while the base weld is made, then the root valve or fitting is made up with sealant or PTFE tape, hand-tight plus one and a half to three turns per ASME B1.20.1 practice, seal-welded where the specification requires. Welding discipline follows the material — preheat and PWHT on chrome-moly, purge and low-carbon filler on stainless — and the base weld's NDT follows the line class. Nothing else: the joint that used to sit between outlet and nipple no longer exists to be welded, inspected or worried about.
Where do nipolets earn their keep — the vibration story?
On the small-bore branches that shake. A root valve standing on a nipple is a mass on the end of a cantilever, and pipework vibration — machinery, flow pulsation, slug flow — works that cantilever at its weakest section. In the old outlet-plus-nipple assembly the weakest section was usually the joint itself: a threaded nipple's root or a fillet weld, sitting exactly at the point of highest bending stress. Small-bore branch fatigue failures of that pattern are one of the industry's best-documented loss causes, and the fixes are equally well known: brace the valve, and remove the joint. The nipolet does the second by construction — base and nipple are one forging, with no thread root or weld at the high-stress section, just forged metal tapering into the reinforced base. It does not repeal fatigue: a heavy valve on any 3½" cantilever still deserves a gusset where vibration is real, and the piping specification's small-bore bracing rules still apply. But it starts the fatigue argument from forged continuity instead of from a joint — which is why vibrating services write the nipolet in by name.
Nipolet, threadolet or sockolet — which one for a valve take-off?
Count the joints between header and valve. With a threadolet or sockolet the path is: outlet welded to the header, then a nipple screwed or welded into the outlet, then the valve on the nipple — two branch joints plus the base weld. With a nipolet the path is: base welded to the header, valve straight onto the integral nipple — one branch joint, or none at all when a plain-end nipolet butt-welds directly to a welded-bonnet valve. Fewer joints mean fewer leak paths, less NDT, and a stronger section where vibration bites, which is why the nipolet is the classic root-valve, drain and vent fitting on headers and vessels. The siblings keep their own ground: the threadolet is the general-purpose female thread for gauges and connections that break by hand; the sockolet is the socket-weld workhorse where the branch is permanent pipe rather than a valve; and above NPS 2 — the nipolet's ceiling — the weldolet takes over regardless. All four share the MSS SP-97 body; their pages on this site carry each story.
Is 'Nipolet' a brand name?
By origin, yes — Nipolet belongs to the same family of Bonney Forge trademarks as Weldolet, Sockolet and Thredolet, and like them it long ago became the word the piping trade actually uses on requisitions, isometrics and shop floors. This page uses it in that ordinary generic sense; the descriptive term is nipple outlet or one-piece branch outlet with integral nipple. What we manufacture and certify are integrally reinforced forged branch outlet fittings to MSS SP-97 with the nipple forged integrally, plain-bevelled or threaded to ASME B1.20.1 — the wording our certificates carry, dimensionally and functionally interchangeable with any outlet made to the same standards. If your documents write 'nipple outlet', 'valve take-off outlet', 'welding nipple outlet' or 'one-piece nipple branch', they mean this product; name the standards and the paperwork follows.
What testing, certification and marking come with nipolets?
The forging's full paper trail. Chemistry and mechanicals per heat on the EN 10204 3.1 MTC — 3.2 witnessed on request — with heat-treatment condition and furnace records where the grade demands them: normalised LF2, N&T chrome-moly, solution-annealed stainless and duplex. Each piece is marked with manufacturer, size, schedule (XS or XXS), material grade and heat number — the heat number tying it to its certificate, its ladle chemistry and its heat-treatment record. On threaded versions the male NPT is gauged to ASME B1.20.1 and the gauging recorded. PMI verifies every alloy piece before dispatch. NDT to the ordered scope: MPI or DPT of the machined body, UT of the forging where specified, hardness testing for sour service, with NACE MR0175 / ISO 15156 compliance available on request. Dimensional inspection reports to MSS SP-97. Third-party witness or review is routine on project orders; state the agency and scope on the enquiry.
Where can I find nipolet dimensions?
In the datasheet on this page — a two-page PDF with the dimension table for all six sizes, ½" through 2", in both XS and XXS. Two dimensions do the work: A, the overall length from outlet base to nipple end, which is the standard 3½" (88.9 mm) across every size; and C, the bore through the nipple, which changes with size and schedule — XS bores match Schedule 80 pipe, XXS bores match Schedule 160/XXS, while the nipple's outside diameter always matches the nominal size. Catalogue dimensions are in inches with millimetre equivalents given alongside, and the table is reproduced on this page for quick reference. Two working notes: the installed height on a specific header depends on the run pipe's curvature as well as A, so stack-ups should state run size and schedule; and non-standard lengths — longer nipples for thick insulation, shorter for tight racks — are forged on request against the same certification.
What details are needed to get an accurate nipolet quotation?
Seven elements plus commercial terms: (1) run pipe size and schedule — the base is contoured to it, e.g. 8" Sch 40; (2) nipple size — ½" to 2"; (3) schedule — XS to match Schedule 80 branches or XXS for Schedule 160/XXS systems; (4) end type — plain (bevelled) for butt welding, or threaded with male NPT to ASME B1.20.1; TOE/POE shorthand is welcome; (5) length — 3½" standard, or state the non-standard length your insulation or rack demands; (6) material grade, exactly as your specification writes it — A105, A350 LF2, A182 F316L, duplex F51, copper-nickel C70600; (7) certification and NDT — EN 10204 3.1 (our standard) or 3.2 witnessed, thread gauging on threaded ends, plus MPI/DPT/UT or NACE scope where extended — then quantity and destination. Send it to sales@tescosteel.com or through the inquiry form; quotations normally return within 24 hours with price, unit weights and delivery, and common A105 and stainless combinations usually quote from stock.
Who manufactures nipolets in India?
Tesco Steel & Engineering is an ISO 9001:2015 certified manufacturer based in Mumbai, India, forging integrally reinforced one-piece branch outlet fittings to MSS SP-97 — nipolets (nipple outlets) in NPS ½" to 2", XS and XXS bores, standard 3½" length, plain-bevelled or with male NPT threads gauged to ASME B1.20.1. Materials span our whole forge: carbon steel A105, LTCS A350 LF2, chrome-moly A182 F11 through F91, stainless 304/316/321/347 families, duplex and super duplex, the nickel alloys, and copper-nickel — the 90/10 C70600 production photographed on this page. PMI verification, per-piece marking tying each fitting to its heat, and EN 10204 3.1/3.2 certification on every lot. The same works supplies the complete olet family — weldolets, sockolets, elbolets, threadolets, latrolets, sweepolets and flangeolets — alongside the flange ranges this site is built around. Exported to more than 50 countries; datasheet with the full dimension table downloadable on this page.
