Tesco Steel & Engineering forges latrolets — the member of the olet family that leaves the header at 45° instead of square: an integrally reinforced lateral branch whose elongated base is butt-welded to the run pipe and whose branch end comes butt-weld, socket-weld or threaded per ASME B16.11 and B1.20.1. The angle is the product — a smoother flow path with lower turbulence and pressure drop for by-passes, blow-down and drain lines and angled take-offs — and because an acute intersection asks more of the branch reinforcement, MSS SP-97 forges the compensation into the body. In NPS ¼″ to 6″ butt-weld and ¼″ to 2″ Classes 3000/6000 and Sch 160/XXS, in every material grade on this site: carbon steel, LTCS, the chrome-moly ladder, stainless — the SS304 threaded production photographed below — duplex and the nickel alloys. Each piece is laser-marked branch × run, class, grade and heat, certified to EN 10204 3.1/3.2. All four dimension tables in the datasheet below. ISO 9001:2015, made in Mumbai, India — exported to 50+ countries.
MSS SP-97 · B16.11 / B1.20.1 EndsLateral Outlet · 45° BranchBW / SW / Threaded — All Three EndsNPS ¼″–6″ · Class 3000 / 6000Lower Turbulence & Pressure DropCarbon Steel to Nickel AlloysEN 10204 3.1 / 3.2 · ISO 9001:2015
SS304 Threaded Latrolets, 1″ × 4″ & ½″ × 2″ #3000 — the 45° Opening That Names the Fitting
What is a Latrolet?
The branch that leans with the flow. A latrolet (also written lateral outlet) is a forged, integrally reinforced branch outlet fitting whose branch leaves the run pipe at 45° instead of 90°. The elongated base is butt-welded to the header over an oval opening cut along the pipe axis; the branch end is butt-weld, socket-weld or threaded per ASME B16.11; reinforcement is forged in per MSS SP-97 — sized for the harder demands an acute intersection makes. The angle buys a smoother flow path: lower turbulence, lower pressure drop — the natural entry for by-passes, blow-down lines, drains and angled take-offs. We forge them NPS ¼″–6″ butt-weld and ¼″–2″ in Classes 3000/6000 and Sch 160/XXS, in every grade from A105 to the nickel alloys, laser-marked and certified to EN 10204 3.1/3.2.
The branch must not throttle what it carries — a 45° entry costs a fraction of a square tee's pressure drop
Blow-down & relief discharge
High-velocity flow punishes square corners — the lateral turns the stream half as hard, easing turbulence and erosion at the heel
Drains
A 45° branch aimed along the flow drains like a funnel, not a pocket
Upstream of instruments
Meters dislike swirl — a lateral disturbs the run less than a 90° take-off
Congested racks
When the branch line runs at 45° anyway, the latrolet makes the angle at the header — no extra elbow, one weld fewer
The latrolet is the forged version of the fabricated 45° stub-in — the detail pipe fitters have always preferred for angled duty, arriving with the lateral's harder reinforcement problem already solved in the body.
The angle is machined into the forging, not fabricated at the spool shop — branch axis at 45° to the run, checked against template, so the fit-up starts from geometry instead of from a protractor and a grinder.
Reinforcement for the Harder Case
An acute intersection removes more metal from the run and concentrates stress harder than a square opening — MSS SP-97's forged-in compensation arrives sized for exactly that, the calculation a fabricated lateral would owe the designer.
All Three Ends
Butt-weld to 6″, socket-weld and threaded to 2″ — the photographed production is the threaded version in SS304, female NPT at 45°, gauged to B1.20.1.
The Elongated Base
A 45° branch meets the run in an ellipse — the base runs long along the pipe axis (dimension B) over an oval opening (length C), spreading the weld and the reinforcement where the lateral geometry needs them.
Specification Notes — Getting Latrolets Right
Three honest notes.The hole is oval and directional: the run-pipe cut-out is elongated along the pipe axis and the fitting leans one way — orient the cut and the branch per the drawing (with the flow for drains and blow-downs) before tacking, because a lateral welded backwards is a lateral cut off. The code treats laterals as their own reinforcement case: B31.3 and B31.1 ask more compensation of an acute branch than a square one — the latrolet's forged-in reinforcement answers it, but where your line class demands a branch calculation for non-perpendicular connections, the designer's word decides. And check the E dimension habit: the branch length along the 45° axis is tabulated for Class 3000/6000 and STD/XS — for Sch 160/XXS butt-weld outlets the catalogue leaves E to be confirmed on request, so ask for it with the quotation when your stack-up needs it.
How Our Latrolets 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
Body machining — the MSS SP-97 lateral profile turned and milled to the tabulated dimensions: height A, base length B, the branch axis at 45°.
3
Saddle contour — the elongated base machined to the run-pipe curvature stated on the order, checked against template with the angle.
4
End preparation — bevel for butt-weld, B16.11 socket bored square to the 45° axis, or NPT thread cut and plug-gauged to B1.20.1 — per the ordered end type.
5
Testing & marking — PMI on alloy grades, MPI/DPT/UT to the ordered scope, then laser marking: grade, end type, branch × run, class, heat number.
6
Certification & packing — EN 10204 3.1 MTC (3.2 witnessed on request); bases, sockets and threads protected, packed sea-worthy.
Where Latrolets Are Used
Wherever a branch should lean instead of stand square: refinery and petrochemical units run their by-passes and blow-down laterals off them; power stations use them on drain headers where flashing condensate hates corners; and process plants put them upstream of the meters and control valves that reward a calm approach. Production pieces below — the marking on each is real:
Inside the 45° — Female NPT at the End of the Slanted Bore, Heats PQ3215 & PQ3218
Latrolet Dimensions — Class 3000 Quick Reference
A is the height from run-pipe surface to branch end, B the base length along the run pipe, C the elongated hole length to cut in the run, E the branch length along the 45° axis; all in millimetres. Set a root gap of about 1.6 mm at the base edge before the butt weld.
NPS (inch)
A (mm)
B (mm)
C (mm)
E (mm)
¼
39.69
59.53
36.51
39.69
⅜
39.69
59.53
36.51
39.69
½
39.69
59.53
36.51
39.69
¾
47.63
69.85
44.45
48.42
1
55.56
82.55
53.98
55.56
1¼
63.50
97.63
66.68
74.61
1½
69.85
107.16
76.99
66.68
2
85.73
138.11
104.78
80.17
Three more tables live in the datasheet: Class 6000 threaded & socket-weld in the same eight sizes, STD/XS butt-weld in twelve sizes from ¼″ to 6″, and Sch 160/XXS butt-weld in seven sizes to 1½″ — where E is supplied on request rather than tabulated. Download the datasheet (PDF) for all four with the dimensional drawing and installation guidance — and for stack-ups on a specific header, state run size and schedule, since the installed height rides on the run pipe's curvature as well as A.
How to Specify & Order a Latrolet
Seven elements — the run pipe shapes the elongated base, so lead with it:
1
Run pipe size and schedule — e.g. 4″ Sch 40; the base is contoured to it.
2
Branch size — ¼″ to 6″ for butt-weld, to 2″ for socket-weld and threaded.
3
Branch end type — butt-weld, socket-weld or threaded (NPT per ASME B1.20.1).
4
Class or schedule — 3000/6000 for SW and threaded; STD/XS or 160/XXS for butt-weld.
5
Material grade, exactly — A105, A350 LF2, A182 F304/304L dual-certified, F22, duplex F51... as your specification writes it.
6
Certification & NDT — EN 10204 3.1 (our standard) / 3.2 witnessed; MPI, DPT, UT or NACE scope if extended — and ask for dimension E with Sch 160/XXS butt-weld outlets when your stack-up needs it.
7
Quantity & destination — to sales@tescosteel.com or the inquiry form; note the branch orientation if the drawing leans the lateral a particular way along the run.
Example: “Latrolet, 1″ branch on 4″ Sch 40 run, threaded NPT per ASME B1.20.1, Class 3000, ASTM A182 F304/304L dual-certified, B31.3, EN 10204 3.1 — 12 pieces.” Quotations normally within 24 hours with price, unit weights and delivery.
Latrolets — Frequently Asked Questions
What is a latrolet (lateral outlet)?
A latrolet is a forged, integrally reinforced branch outlet fitting that leaves the run pipe at 45° instead of the square 90° every other olet takes. The contoured base is butt-welded to the header over an elongated opening cut along the pipe axis; the branch end is supplied butt-weld (bevelled), socket-weld or threaded per ASME B16.11, and the reinforcement is forged into the body per MSS SP-97 — no pads, no fabricated gussets. The angle is the product: a 45° entry gives the flow a smoother path than a square tee, with lower turbulence and pressure drop, which is why laterals carry by-passes, blow-down lines, drains and angled take-offs. We forge latrolets in NPS ¼" to 6" for butt-weld duty and ¼" to 2" in Classes 3000/6000 and Sch 160/XXS, in every material grade on this site, each laser-marked and certified to EN 10204 3.1/3.2.
Why a 45° branch — what does the angle buy?
Flow that turns half as hard. A 90° branch asks the fluid to make a square turn: the flow separates at the corner, eddies form, and the branch entry costs pressure drop and, in dirty or fast services, erosion at the heel. A 45° lateral halves that turn, and the benefits follow directly: lower entry loss for by-pass lines that must not throttle what they carry; gentler flow for blow-down and relief lines, where high-velocity discharge punishes square corners; a natural downhill path for drains, since a 45° branch aimed along the flow drains a line the way a funnel does rather than the way a pocket does; and less disturbance upstream of meters and instruments that dislike swirl. None of this is exotic — pipe fitters have preferred laterals for angled duty since piping began. The latrolet packages that preference as a forged, code-reinforced fitting instead of a fabricated lateral cut and welded in the field.
What standards cover latrolets?
The family's usual division, with the angle adding one twist. MSS SP-97 — Integrally Reinforced Forged Branch Outlet Fittings — owns the body: forged-in reinforcement, pressure-temperature basis, marking, materials cross-references. ASME B16.11 owns the socket dimensions on socket-weld ends and B1.20.1 the NPT taper on threaded ends, so branch pipe fits a latrolet exactly as it fits a coupling. On the line, branch reinforcement logic is the piping code's — B31.3 or B31.1 — and here the angle matters: the codes treat a lateral branch as its own reinforcement case, because an acute intersection removes more metal from the run and concentrates stress harder than a 90° opening. That is precisely why the latrolet's compensation is forged into the body rather than improvised: the fitting arrives with the lateral's harder reinforcement problem already solved. Materials certify to their own standards — A105, A350 LF2, A182, B564 — and the certificate reads like any forging certificate, with the geometry spelled out in the marking: the pieces photographed here read '1" X 4" 3000#', branch × run, class, heat.
What sizes, classes and schedules do latrolets come in?
Branch sizes run NPS ¼" through 6" for butt-weld STD/XS duty — the widest range — and ¼" through 2" everywhere else: Class 3000 and 6000 for socket-weld and threaded ends, Sch 160 and XXS for heavy-wall butt-weld. The class-to-schedule habits are the family's usual ones — socket and threaded ends carry the fitting class, butt-weld ends are schedule-matched to the branch pipe. Like every olet, a latrolet is a reducing fitting sized branch-on-run: the pieces photographed on this page are marked 1" × 4" and ½" × 2", branch × run, and each catalogue size covers a run range, so state the actual run size and schedule and the base comes contoured to it. One geometric note the 45° adds: the base is longer than a 90° olet's — dimension B in the datasheet runs along the pipe axis to carry the slanted branch, and the hole C is elongated rather than round. The four dimension tables in the datasheet carry all of it, size by size.
What branch ends do latrolets come with?
All three, like the elbolet — the lateral's duties span every small-bore habit. Butt-weld: the branch end is bevelled for a full-penetration weld, the choice for process-rated laterals and the only end that runs the full ¼" to 6" range. Socket-weld: a B16.11 socket at 45° — square-cut pipe in, withdraw about 1.5 mm for the root gap, fillet-weld — for welded small-bore laterals to NPS 2. Threaded: a female NPT taper per ASME B1.20.1, for laterals that must come apart — the production pieces photographed on this page are exactly that, SS304 threaded latrolets in ½" × 2" and 1" × 4", Class 3000, laser-marked with their heats. The end type travels with class and schedule as usual: 3000/6000 for socket and threaded, STD/XS or 160/XXS for butt-weld. State the end with the sizes and the angle takes care of itself — it is always 45° to the run.
Why does the piping code ask more of a lateral branch?
Because the acute angle cuts a bigger hole and loads it harder. Slice a cylinder at 90° and the opening is a circle; slice it at 45° and the opening stretches into an ellipse — more metal gone from the pressure envelope along the run axis, exactly where the hoop stress needs it. The crotch of the acute corner concentrates stress on top of that. ASME B31.3 and B31.1 recognise this: their branch reinforcement rules handle laterals as a distinct case, requiring more compensation as the angle closes, and many company specifications require a calculation or a qualified fitting for any non-perpendicular branch. This is the latrolet's whole reason for being forged: the MSS SP-97 body puts the extra metal where the lateral geometry demands it, proven by the standard's pressure-temperature basis, so the designer specifies a catalogue fitting instead of calculating a reinforced fabricated lateral from scratch. The honest limit runs the same direction — where a specification restricts laterals in severe cyclic service, the designer's word decides, exactly as with any branch detail.
What materials are latrolets available in?
Every grade this site forges. Carbon steel A105 and low-temperature A350 LF2 cover the general and cold benches; chrome-moly A182 F11, F22, F5, F9 and F91 follow steam and hydrogen circuits; stainless F304/304L and F316/316L with dual certification where heats qualify, plus stabilised F321 and F347 — the production pieces photographed on this page are SS304, threaded, laser-marked for a process order; 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. The lateral follows the header's metallurgy grade for grade, and the material pages across this site carry each grade's story. Chemistry per heat, PMI on alloy grades, EN 10204 3.1/3.2 on every lot.
How is a latrolet installed?
Like its siblings, with two disciplines the angle adds: the hole and the orientation. The opening cut in the run pipe is not round — it is elongated along the pipe axis to the datasheet's C length, because the 45° branch meets the run in an ellipse. It is also directional: the cut-out and the fitting must be oriented so the branch leans the way the drawing shows — with the flow for a drain or blow-down entry, against it where the process asks. The contoured base is then fitted with a 1.6 mm root gap, the 45° angle checked before tacking — a bevel gauge on the branch against the run pipe catches a lean before the weld sets it — and the base joined with a full-penetration groove weld. The branch connection follows its end type: butt weld on bevelled ends; the socket habit — insert, withdraw about 1.5 mm, fillet-weld — on socket ends; sealant and hand-tight plus 1½–3 turns on threaded ends. Welding discipline follows the material, and NDT of the base weld follows the line class.
Latrolet or weldolet — when does the branch need the angle?
When the line's geometry or its flow says 45°. The weldolet and its siblings answer the perpendicular case — the overwhelming majority of branches, where the take-off simply leaves the header square. The latrolet answers two situations the square fitting cannot. Geometry: when the branch line must run at 45° anyway — a by-pass rejoining a main, a drain heading down to a header at an angle, a line threading a congested rack — a latrolet makes the angle at the header instead of adding an elbow one weld later; one fitting, one weld, no extra direction change. Flow: when the entry loss and turbulence of a square branch matter — blow-down and relief discharge, erosive or flashing services, connections upstream of flow instruments. Where neither applies, the 90° family is simpler and cheaper: the weldolet, sockolet and threadolet pages on this site carry those stories. And where a fabricated 45° stub-in is on the drawing instead, the latrolet is the forged, pre-reinforced version of exactly that detail.
Is 'Latrolet' a brand name?
By origin, yes — Latrolet belongs to the same family of Bonney Forge trademarks as Weldolet, Sockolet, Thredolet, Elbolet and Nipolet, 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 lateral outlet or 45° branch outlet fitting. What we manufacture and certify are integrally reinforced forged branch outlet fittings to MSS SP-97 with the branch at 45°, socket and threaded ends dimensioned to ASME B16.11 and B1.20.1 — the wording our certificates carry, dimensionally and functionally interchangeable with any outlet made to the same standards. If your documents write 'lateral outlet', '45 degree olet', 'angled branch outlet' or 'lateral boss', they mean this product; name the standards and the paperwork follows.
What is marked on each latrolet?
Manufacturer, material grade, end type, branch × run size, class and heat number — laser-marked on the machined body. The production pieces photographed on this page read exactly that way: 'SS304 LATROLET THREADED 1" X 4" 3000# PQ3215 INDIA' on the larger pair and 'SS304 LATROLET THREADED 1/2" X 2" 3000# PQ3218 INDIA' on the smaller — grade, product, end type, branch × run, class, heat and origin in one line. The branch-times-run convention matters on a lateral for the same reason it does on any reducing olet: it is the fitting's geometry in shorthand, and it is what stores check against the isometric before a spool ships. The heat number ties each piece to its EN 10204 certificate, its ladle chemistry and its heat-treatment record. PMI confirms alloy grades match the mark before dispatch, and project-specific marking — tag numbers, PO references — is applied to order and recorded on the documents.
What testing and certification come with latrolets?
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. PMI verifies every alloy piece. Threads on threaded versions are gauged to ASME B1.20.1 and sockets machined to B16.11. NDT to the ordered scope: MPI or DPT of the machined body and the acute crotch region, 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 and B16.11 — including the 45° angle and the elongated base against template, because on this fitting the angle is the geometry. Third-party witness or review is routine on project orders; state the agency and scope on the enquiry.
Where can I find latrolet dimensions?
In the datasheet on this page — a three-page PDF with four dimension tables: Class 3000 threaded and socket-weld in eight sizes from ¼" to 2"; Class 6000 threaded and socket-weld in the same eight sizes; STD/XS butt-weld in twelve sizes from ¼" to 6"; and Sch 160/XXS butt-weld in seven sizes to 1½". Each tabulates the height A from run-pipe surface to branch end, the base length B along the run pipe, the elongated hole length C to cut in the run, and — for three of the four tables — the branch length E along the 45° axis; E is not catalogued for Sch 160/XXS butt-weld outlets and is supplied on request. The Class 3000 table is reproduced on this page for quick reference. Working notes: the installed height on a specific header rides on the run pipe's curvature as well as A; the hole is cut along the pipe axis, not round; and the root gap of about 1.6 mm belongs in the fit-up. Non-standard angles and drawing-specific variants are machined to order.
What details are needed to get an accurate latrolet quotation?
Seven elements plus commercial terms: (1) run pipe size and schedule — the elongated base is contoured to it, e.g. 4" Sch 40; (2) branch size — ¼" to 6" for butt-weld, to 2" otherwise; (3) branch end type — butt-weld, socket-weld or threaded, with thread form where it matters; (4) class or schedule — 3000/6000 for socket and threaded ends, STD/XS or 160/XXS for butt-weld; (5) material grade, exactly as your specification writes it — A105, A350 LF2, A182 F304/304L dual-certified, duplex F51; (6) certification and NDT — EN 10204 3.1 (our standard) or 3.2 witnessed, plus MPI/DPT/UT or NACE scope where extended; (7) quantity and destination — and the branch orientation if your drawing leans the lateral a particular way along the run. 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 stainless and carbon steel combinations usually quote from stock.
Who manufactures latrolets in India?
Tesco Steel & Engineering is an ISO 9001:2015 certified manufacturer based in Mumbai, India, forging integrally reinforced branch outlet fittings to MSS SP-97 with the branch at 45° — latrolets (lateral outlets) in NPS ¼" to 6", butt-weld, socket-weld and threaded ends per ASME B16.11 and B1.20.1, Classes 3000/6000 and STD/XS to Sch 160/XXS. Materials span our whole forge: carbon steel A105, LTCS A350 LF2, chrome-moly A182 F11 through F91, stainless 304/316/321/347 families — the SS304 threaded production photographed on this page — duplex and super duplex, and the nickel alloys, with copper-nickel and titanium against enquiry. PMI verification, laser marking tying each piece 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, nipolets, sweepolets and flangeolets — alongside the flange ranges this site is built around. Exported to more than 50 countries; datasheet with all four dimension tables downloadable on this page.
