Sweepolet (Contoured Body Outlet) — MSS SP-97 Low-SIF Branch Outlets
Tesco Steel & Engineering forges sweepolets — the olet family's aristocrat: a contoured, integrally reinforced butt-weld branch outlet whose swept body blends into the run pipe through a large-radius contour instead of standing on it like a boss. The shape buys the two things critical lines pay for: a low stress-intensification factor — the fatigue performance that lets cycling main steam, feedwater, pipeline and header branches pass their flexibility analysis — and a full-penetration attachment butt weld that radiography and ultrasonics can fully examine, girth-weld style. The largest sizes in the family: outlets NPS 1¼″ to 24″ on run pipe NPS 6″ to 36″, each contoured to the stated run OD and bevelled to the branch schedule, in every material grade on this site: carbon steel, LTCS, the chrome-moly power bench, stainless, duplex and the nickel alloys. Marked outlet × run, schedule, grade and heat per MSS SP-97, certified to EN 10204 3.1/3.2 with UT/RT scope to order. Dimension table in the datasheet below. ISO 9001:2015, made in Mumbai, India — exported to 50+ countries.
MSS SP-97 · Contoured BodyLow SIF · Fatigue PerformanceRT / UT Examinable Butt WeldOutlets 1¼″–24″ · Runs 6″–36″Contoured to Stated Run ODCarbon Steel to Nickel AlloysEN 10204 3.1 / 3.2 · ISO 9001:2015
Big-Bore Carbon Steel Sweepolet at Our Works — the Swept Contour That Buys the Low SIF
What is a Sweepolet?
The branch that blends instead of standing. A sweepolet (also written contoured body outlet) is a forged, integrally reinforced butt-weld branch outlet whose base merges into the run pipe through a large-radius swept contour. The shape delivers two things: a low stress-intensification factor — the fatigue number flexibility analysis runs on — and a full-penetration attachment butt weld open to complete RT/UT examination. Reinforcement is forged in per MSS SP-97; both ends are butt-weld, the branch end bevelled to match the branch schedule. It is the branch fitting of main steam and feedwater lines, transmission pipelines and critical headers. We forge them in outlets NPS 1¼″–24″ on runs 6″–36″, contoured to the stated run OD, in every grade from A105 to the nickel alloys, certified to EN 10204 3.1/3.2.
Low SIF — the load spreads along the contour; fatigue analysis rewards it
Attachment weld
Groove weld at a boss — surface NDT, awkward for RT
Full-penetration butt weld on an open contour — RT and UT examine it like a girth weld
Profile above the run
Tall boss
Low — minimal height, friendly to tight envelopes
Size ceiling
Practical to ~24″ branch (weldolet)
Outlets to 24″ on runs to 36″ — built for big bore
Both properties come from one shape: the sweep that lowers the stress concentration is the same open contour that gives the radiographer a clean shot. Critical-service codes ask for both — which is why they name this fitting.
Instrument and level connections straight to a flange face
All eight share the MSS SP-97 integrally reinforced body — and with this page, every fitting in the family is live in this menu: weldolet, sockolet, elbolet, threadolet, nipolet, latrolet, sweepolet and flangeolet, all from the same works.
What You're Buying in the Forging
The Low SIF
The swept contour spreads load transfer over a long, smooth transition — the lowest stress-intensification factor in the olet family, which is what lets cycling branches pass fatigue and flexibility analysis.
The Provable Weld
A full-penetration butt weld on an open contour — radiography shoots it and ultrasonics scan it like a girth weld, satisfying the volumetric examination critical specifications demand of branch attachments.
Contoured to Your Run
Each sweepolet is forged and machined against one run-pipe OD — the sweep merges tangentially into the stated header, which is why the order carries outlet × run × schedules, always both sizes.
Big Bore, Low Profile
Outlets to 24″ on runs to 36″, with minimal height above the run — the forged, integrally reinforced answer where fabricated and pad-reinforced branches would put uninspectable welds in a critical line.
Specification Notes — Getting Sweepolets Right
Three honest notes.Never order without the run size: the body is contoured to one run-pipe OD — a sweep cut for a 16″ header will not blend on a 24″ one, so the enquiry carries outlet × run × schedules, both sizes, every time. Height A is a minimum, not a promise: the installed height depends on the run OD the fitting is contoured to — for stack-ups, ask us to confirm the height for your combination with the quotation. And buy the contour only where it earns: on a static line with standard examination, the weldolet does the job for less — the sweepolet's premium pays where fatigue analysis, volumetric weld examination or big-bore branches rule the specification, and that is the designer's call, not the catalogue's.
How Our Sweepolets 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
Forging the sweep — the contoured, low-profile body forged with the reinforcement in the blend radius — the metal is in the sweep, not in a boss.
3
Contour machining — the base machined to the run-pipe OD stated on the order and checked against template — on this fitting the contour is the specification.
4
End preparation — the branch end bevelled to match the ordered branch schedule — STD, XS, Sch 160, XXS or as specified — and the attachment edge prepared for the full-penetration butt weld.
5
Testing & marking — PMI on alloy grades, MPI/DPT/UT/RT to the ordered scope, then marking per MSS SP-97: outlet × run, schedule, grade, heat number.
6
Certification & packing — EN 10204 3.1 MTC (3.2 witnessed on request); contours and bevels protected, packed sea-worthy.
Where Sweepolets Are Used
Wherever a big branch meets an unforgiving specification: power stations put them on main steam, hot reheat and feedwater branches in the chrome-moly grades; oil and gas transmission runs its offtakes and launcher connections through them under B31.4/B31.8 welding practice; process plants specify them on large critical headers and under B31.3 severe cyclic conditions; and offshore modules use the low profile where envelope is tight. Production below — a big-bore piece at our works:
The Sweep from the Side — Saddle Skirt Flaring into the Run-Pipe ContourFrom Above — the Bevelled Branch End Inside the Wide Contoured Base
Sweepolet Dimensions — Quick Reference
A is the minimum height from run-pipe surface to branch weld end — the actual height varies with the run OD the fitting is contoured to; B is the outside diameter of the contoured base at the run pipe. Catalogue dimensions in inches, millimetres in brackets.
Outlet NPS (inch)
Run Pipe Range (NPS)
A* — Height
B — Base OD
1¼
6 – 36
1¼ (31.8)
4 (101.6)
1½
6 – 36
1¾ (44.4)
5½ (139.7)
2
6 – 36
1½ (38.1)
5½ (139.7)
3
6 – 36
1 21/32 (42.1)
7 (177.8)
4
6 – 36
2 1/32 (51.6)
8¾ (222.2)
6
10 – 36
2 11/16 (68.3)
13 (330.2)
8
12 – 36
3 (76.2)
15 (381.0)
10
16 – 36
3⅛ (79.4)
18½ (469.9)
12
16 – 36
3 5/16 (84.1)
20½ (520.7)
14
20 – 36
3⅝ (92.1)
24 (609.6)
16
24 – 36
3¾ (95.2)
28 (711.2)
18
24 – 36
4⅝ (117.5)
31 (787.4)
20
24 – 36
5⅛ (130.2)
33 (838.2)
24
30 – 36
5⅝ (142.9)
38 (965.2)
The run-range column is the sizing rule in one glance: the bigger the outlet, the bigger the run it needs to blend into — a 24″ outlet lives only on 30″–36″ headers. Download the datasheet (PDF) for the table with the dimensional drawing and installation guidance — and state outlet × run × schedules for a confirmed installed height on your combination.
How to Specify & Order a Sweepolet
Six elements — and the first two are never optional, because the body is contoured to your run:
1
Outlet size and schedule — e.g. 8″ Sch 80; the bevel matches the branch pipe.
2
Run pipe size and schedule — e.g. 16″ Sch 60; the whole body is contoured to that OD — never one size without the other.
3
Material grade, exactly — A105, A350 LF2, A182 F22 Cl.3, F91, F316L... as your specification writes it.
4
Certification & NDT — EN 10204 3.1 (our standard) / 3.2 witnessed; MPI, DPT, UT, RT or NACE scope as your line class demands.
5
Project marking — tag numbers, weld-map identifiers, PO references, applied to order.
6
Quantity & destination — to sales@tescosteel.com or the inquiry form; state required delivery — large and alloy sizes are typically forged against order.
Example: “Sweepolet, 8″ Sch 80 outlet on 16″ Sch 60 run, ASTM A182 F22 Cl.3, B31.1, EN 10204 3.2, UT of forging + RT of attachment weld by others — 2 pieces.” Quotations normally within 24 hours with price, unit weights and delivery.
Sweepolets — Frequently Asked Questions
What is a sweepolet (contoured body outlet)?
A sweepolet is a forged, integrally reinforced butt-weld branch outlet whose body is contoured — swept — so that the base blends into the run pipe through a large-radius curve instead of standing on it like a boss. Two consequences follow from that shape, and they are the fitting's whole identity. First, the smooth transition gives a low stress-intensification factor: pressure cycles, thermal cycles and bending moments concentrate far less at the branch than they do at an abrupt intersection. Second, the attachment weld is a full-penetration butt weld laid along an open, accessible contour, so radiography and ultrasonics can examine it completely — the property critical-service codes prize. It is the branch fitting for large-diameter, high-pressure, cyclic and critical lines: main steam, feedwater, transmission pipelines, process headers. We forge sweepolets in outlet sizes NPS 1¼" to 24" for run pipe NPS 6" to 36", contoured to the stated run OD, in every material grade on this site, certified to EN 10204 3.1/3.2.
What does 'low stress-intensification factor' mean — and why does it matter?
A stress-intensification factor (SIF) is the piping code's multiplier for how much a component magnifies cyclic stress compared with plain pipe: a butt weld in straight pipe sits near 1.0, while an unreinforced fabricated branch can run several times that. Every branch connection is a hole in a pressure envelope with welds around it, so every branch magnifies stress — the only question is by how much. The sweepolet's answer is geometry: the swept, large-radius contour spreads the load transfer over a long, smooth transition instead of a sharp corner, and the integral reinforcement lives in that same contour. The result is the lowest SIF in the olet family, which is exactly what fatigue analysis rewards. On lines that cycle — power piping that heats up and cools down, pipelines that pack and unpack, headers behind reciprocating machines — flexibility and fatigue calculations run directly on these factors, and the sweepolet is specified because it makes those calculations pass. On a line that never cycles, the premium buys less; the comparison question below is honest about that.
Why is the fully examinable weld the sweepolet's calling card?
Because on critical lines, the weld you cannot examine is the weld you cannot trust. A conventional olet attaches through a groove weld buried at the base of a boss — sound practice, examinable by MPI or DPT at the surface and UT with skill, but geometrically awkward for radiography. The sweepolet's attachment is different in kind: a full-penetration butt weld running around an open, swept contour, with access from both sides of the joint line — geometry that RT can shoot and UT can scan as readily as a girth weld. That is precisely what the severe-duty codes and specifications ask: power piping to ASME B31.1 and boiler external piping demand volumetric examination of main steam and feedwater branch welds; pipeline codes B31.4 and B31.8 want girth-weld-quality records on every joint in the right-of-way; and critical process headers under B31.3 severe cyclic conditions carry 100% RT requirements. The sweepolet exists so a large branch connection can meet those demands with a catalogue fitting — the weld is not just strong, it is provable.
What standards cover sweepolets?
MSS SP-97 — Integrally Reinforced Forged Branch Outlet Fittings — owns the fitting: the contoured body, its reinforcement, pressure-temperature basis, marking and material cross-references, exactly as for the rest of the olet family. Both ends are butt-weld, so ASME B16.11's sockets and B1.20.1's threads play no part here: the branch end is bevelled to match the branch pipe's schedule — STD, XS, Sch 160, XXS or as specified — and welding follows the governing code's rules for butt joints. On the line, the branch reinforcement logic and the fatigue treatment belong to the piping code — B31.1 for power, B31.3 for process, B31.4 and B31.8 for liquid and gas transmission — and it is their stress-intensification and examination rules that make the sweepolet's case. Materials certify to their own standards — A105, A350 LF2, A182, B564 — so the certificate reads like any forging certificate, with the marking carrying outlet size, run size, schedule, grade and heat per MSS SP-97.
What sizes do sweepolets come in?
The largest range in the olet family — this is the big-bore branch fitting. Outlet sizes run NPS 1¼" through 24" (DN 32 to DN 600), on run pipe from NPS 6" to 36". The catalogue pairs each outlet with a minimum run: outlets to 4" fit runs from NPS 6 up; a 6" outlet needs a 10" run; an 8" needs 12"; 10" and 12" outlets need 16"; 14" needs 20"; 16" and 18" need 24"; and the 24" outlet sits on runs of 30" to 36". The logic is geometric — the swept base must land on enough run-pipe circumference to blend its contour, and a large outlet on a small run would leave no run to blend into. Fourteen tabulated outlet sizes carry a base OD from 4" (101.6 mm) for the smallest to 38" (965.2 mm) for the 24" — the photographed piece on this page shows why that footprint dwarfs a weldolet's. Height A is tabulated as a minimum and grows with the run OD the fitting is contoured to; the sizing question below explains that habit.
Why must I state the run pipe size — and why is height A only a minimum?
Because a sweepolet is not a generic saddle — it is contoured to one run-pipe outside diameter. The swept base must merge tangentially into the header's curvature, and a contour cut for a 16" run will not blend on a 24" one: the sweep lands at the wrong angle and the whole low-stress argument evaporates at the fit-up. So every sweepolet is machined against the run size and schedule stated on the order, and the enquiry must carry both sizes — outlet and run — plus schedules for each. Height A follows the same logic: the catalogue tabulates it as a minimum because the distance from run-pipe surface to branch weld end depends on how the fixed swept body sits on the particular run OD — a flatter, larger run holds the branch end higher above its surface than a tightly curved small one. For stack-up calculations, state outlet × run × schedules and we confirm the installed height for that combination on the order — the same run-specific honesty the weldolet page's run-range discipline describes, taken one step further.
What materials are sweepolets available in?
Every grade this site forges, led by the grades critical services actually order. Carbon steel A105 covers general headers and the pipeline bench — the large production piece photographed on this page is carbon steel, contoured for a big-bore header; low-temperature A350 LF2 takes the cold side. The chrome-moly ladder — A182 F11, F22, F5, F9 and F91 — is classic sweepolet territory, because main steam and hot reheat branches are exactly where the fitting's fatigue performance and examinable welds are specified; F91's paperwork discipline applies to its fittings as much as its flanges. 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 bench — Monel, Inconel, Incoloy, Hastelloy — with copper-nickel and titanium against enquiry. Chemistry per heat, PMI on alloy grades, EN 10204 3.1/3.2 on every lot.
How is a sweepolet installed?
Like a butt-weld fitting, not like a boss. The opening in the run pipe is cut to the outlet bore and its edge prepared; the contoured base is offered up and the fit verified around the whole sweep before tacking — a properly contoured base should follow the run's curvature closely along its entire edge, because the attachment weld's quality begins at that fit. The attachment weld is a full-penetration butt weld around the contoured base, made to the governing code's procedure, and then examined the way the service demands: RT or UT volumetric examination is the point of the geometry, so critical lines shoot or scan this weld like a girth weld and file the record. The branch pipe then butt-welds to the bevelled outlet end, schedule matched, as an ordinary butt joint. Welding discipline follows the material — preheat and PWHT on chrome-moly, purge and low-carbon filler on stainless — and on power and pipeline work the weld documentation travels with the line's dossier. No root gaps to set, no threads to protect: two butt welds, both provable.
Sweepolet or weldolet — when does the branch deserve the contour?
When fatigue or examination rules the specification — and honestly, not before. The weldolet is the default 90° branch for good reason: simpler forging, lower price, quicker delivery, fine wherever the line's duty is static and the standard groove-weld examination satisfies the code. The sweepolet earns its premium in three situations. Cyclic duty: lines that breathe — power piping through startups, pipelines through packing cycles, headers behind pulsating machines — where flexibility analysis runs on stress-intensification factors and the swept contour's low SIF makes the calculation pass. Mandatory volumetric examination: where the specification demands RT or UT of branch attachment welds, the sweepolet's butt-weld geometry delivers a provable weld a boss cannot. Large bores: at 10", 16", 24" outlet sizes, the sweepolet is often the only forged, integrally reinforced option on the table, against fabricated and pad-reinforced alternatives whose welds and fatigue behaviour are exactly what the fitting exists to avoid. Where none of the three applies, order the weldolet and bank the difference — its page on this site tells that story.
Is 'Sweepolet' a brand name?
By origin, yes — Sweepolet belongs to the same family of Bonney Forge trademarks as Weldolet, Sockolet, Thredolet, Elbolet, Nipolet and Latrolet, 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 contoured body outlet or contoured integrally reinforced branch outlet. What we manufacture and certify are integrally reinforced forged branch outlet fittings to MSS SP-97 with the swept, contoured profile, both ends butt-weld — the wording our certificates carry, dimensionally and functionally interchangeable with any outlet made to the same standard. If your documents write 'contoured outlet', 'swept branch outlet', 'low-SIF branch fitting' or 'contoured body fitting', they mean this product; name the standard and the paperwork follows.
What is marked on each sweepolet?
Manufacturer, outlet size, run size, schedule, material grade and heat number — per MSS SP-97, applied to the body where the contour leaves room and the service leaves it legible. The outlet-times-run convention carries more weight here than anywhere else in the family, because a sweepolet is contoured to one specific run OD: the marking is what tells stores, and the fit-up crew after them, that this particular fitting belongs on the 16" header and not the 20" one beside it — two fittings that can look deceptively similar lying on a rack. The heat number ties each piece to its EN 10204 certificate, its ladle chemistry and its heat-treatment record, exactly as across the rest of our production. PMI confirms alloy grades match the mark before dispatch, and project-specific marking — tag numbers, PO references, weld-map identifiers for pipeline work — is applied to order and recorded on the documents.
What testing and certification come with sweepolets?
The forging's full paper trail, with the volumetric options this fitting exists to serve. 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. PMI verifies every alloy piece. NDT to the ordered scope: MPI or DPT of the machined contour, UT of the forging, and RT capability noted because the fitting's whole geometry is built for radiographic practice at the installation stage — many purchasers mirror that in the forging examination too. Hardness testing for sour service, with NACE MR0175 / ISO 15156 compliance available on request. Dimensional inspection reports to MSS SP-97, including the contour against the stated run OD, because on this fitting the sweep is the specification. Third-party witness or review is routine on power and pipeline orders; state the agency and scope on the enquiry.
Where can I find sweepolet dimensions?
In the datasheet on this page — a two-page PDF with the dimension table for all fourteen outlet sizes, 1¼" through 24", reproduced on this page for quick reference. Three columns do the work: the run pipe size range each outlet fits, from NPS 6–36 for the small outlets to NPS 30–36 for the 24"; the height A from run-pipe surface to branch weld end, tabulated as a minimum from 1¼" (31.8 mm) to 5⅝" (142.9 mm); and the base outside diameter B at the run pipe, from 4" (101.6 mm) to 38" (965.2 mm). Catalogue dimensions are in inches with millimetre equivalents alongside. The honest asterisk sits on A: it is a minimum because the actual installed height depends on the run-pipe OD the fitting is contoured to — state outlet × run × schedules and we confirm the height for that combination on the order. Bevels are cut to match the branch schedule — STD, XS, Sch 160, XXS or as specified — and drawing-specific variants are machined to order.
What details are needed to get an accurate sweepolet quotation?
Six elements plus commercial terms — fewer ends to choose than the family's small-bore members, but both sizes are mandatory: (1) outlet size and schedule — e.g. 8" Sch 80, since the bevel matches the branch pipe; (2) run pipe size and schedule — e.g. 16" Sch 60, since the whole body is contoured to that OD; never one without the other; (3) material grade, exactly as your specification writes it — A105, A350 LF2, A182 F22 Cl.3, F91, F316L; (4) certification and NDT — EN 10204 3.1 (our standard) or 3.2 witnessed, plus the MPI/DPT/UT/RT scope your line class demands and NACE where it applies; (5) any project marking — tag numbers, weld-map identifiers, PO references; (6) 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. Large and alloy sizes are typically forged against order — state the required delivery with the enquiry and we confirm schedule with the quotation.
Who manufactures sweepolets in India?
Tesco Steel & Engineering is an ISO 9001:2015 certified manufacturer based in Mumbai, India, forging integrally reinforced contoured branch outlet fittings to MSS SP-97 — sweepolets (contoured body outlets) in outlet sizes NPS 1¼" to 24" for run pipe NPS 6" to 36", each contoured to the stated run OD, bevelled to match the branch schedule. Materials span our whole forge: carbon steel A105 — the big-bore production photographed on this page — LTCS A350 LF2, chrome-moly A182 F11 through F91 for the power bench, stainless 304/316/321/347 families, duplex and super duplex, and the nickel alloys against enquiry. PMI verification, MSS SP-97 marking with outlet, run, schedule, grade and heat, and EN 10204 3.1/3.2 certification on every lot, with UT and RT scope to order. This page completes the olet family from the same works — weldolets, sockolets, elbolets, threadolets, nipolets, 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.
