NF NU-FLOW TEGUH

Technical register ยท 26 memos on file

The insights register.

Every memo answers one procurement question, in writing, with the standards named and caveated.

ANSWER

Insights is NF Teguh's library of practical valve articles: what testing standards verify, how material certificates differ, how to choose between valve patterns, and what nameplate markings mean. Each piece answers one procurement question in plain language so a buyer can specify with confidence. New articles are added as questions come in from Malaysian plants, contractors and purchasers.

GUIDES

Start here: the two guides

Two longer pieces anchor the register. One walks specification from line conditions to a purchase order. The other walks the paperwork: certificates, test reports and markings. Every memo below hangs off one of them.

REFSUBJECTFILED
MEMO-01 Specifying industrial valves: from line conditions to purchase order 2026-08-19 Specifying an industrial valve means turning line conditions into an unambiguous purchase order: fluid, pressure and temperature first, then valve type, pressure class, materials, end connection, operator and the paperwork required. MEMO-02 Valve procurement documentation: EN 10204 certificates, API 598 testing and MSS SP-25 marking 2026-08-19 Valve procurement paperwork answers three questions. What material is this? EN 10204 certificates. Was it tested? API 598 reports. What am I looking at? MSS SP-25 markings.

Reference sheets: Gate valve vs globe valve, Ball valve vs butterfly valve and ASME pressure class reference.

MEMOS

Technical memos

Filed as questions come in from Malaysian plants, contractors and purchasers: testing, certification, pattern selection, markings. Each is a few minutes' read and ends at what to state on the enquiry.

REFSUBJECTFILED
MEMO-03 Fire-safe valves: API 607 vs API 6FA and when a spec asks for them 2026-08-19 Fire-safe means a valve keeps a defined degree of shutoff after a standard fire test, not that it is fireproof. MEMO-04 NACE MR0175 and sour service: what it means when a valve line names it 2026-08-19 NACE MR0175, now paired with ISO 15156, limits materials for sour service (hydrocarbon streams carrying hydrogen sulphide), because sulphide stress cracking breaks susceptible steels. MEMO-05 What OS&Y means and why rising-stem gate valves dominate isolation duty 2026-08-19 OS&Y stands for outside screw and yoke: the gate valve's stem threads run in a yoke outside the pressure boundary, so the threads never touch the process fluid and the rising stem shows open or shut at a glance. MEMO-06 Specifying pressure class: what Class 150, 300 and 600 actually mean 2026-08-19 Class 150, Class 300 and Class 600 are not working pressures. MEMO-07 EN 10204 3.1 vs 3.2 certificates: what procurement actually needs 2026-08-19 EN 10204 defines material document types, and the practical choice is between type 3.1 and type 3.2. MEMO-08 API 598 valve testing explained: what a shell and seat test report shows 2026-08-19 API 598 is the inspection and testing standard most valve purchase orders cite. MEMO-09 Trunnion or floating: choosing a ball valve mounting 2026-08-19 In a floating ball valve the ball is held only by its seats, and line pressure pushes it onto the downstream seat: simple and economical at small sizes and moderate classes. MEMO-10 Wafer, lug or double-flanged: choosing a butterfly valve body 2026-08-19 Wafer bodies clamp between line flanges and are the lightest and cheapest. Lug bodies carry threaded inserts so a line can be dead-ended on one side. Double-flanged bodies bolt to each flange and suit larger sizes and critical or buried service. MEMO-11 Check valve types: swing, dual-plate and piston, and where each fits 2026-08-19 Swing, dual-plate and piston check valves all stop reverse flow but behave differently. MEMO-12 Reading a valve nameplate: MSS SP-25 marking explained 2026-08-19 A valve nameplate marked to MSS SP-25 identifies the valve: manufacturer, size, pressure class or rating, body and trim material grades, and often the governing standard and heat identification. MEMO-13 API 600 vs API 602: gate valve standards compared 2026-09-17 API 600 and API 602 differ in scope, not rank. For a gate valve between NPS 1 and NPS 4, the purchase order must name the standard. MEMO-14 ASME B16.10 valve face-to-face dimensions explained 2026-09-19 ASME B16.10 fixes a valve's installed length. A replacement fits only when type, size, class, end, facing and pattern all match. MEMO-15 BS 1873 vs API 623: globe valve standards compared 2026-09-26 BS 1873 and API 623 do not cover the same globe valves. Below NPS 2 there is no API 623 valve to quote, and both standards cover stop-check valves. MEMO-16 RF, FF or RTJ: what a valve's flange face means 2026-09-30 RF is a raised face, FF a flat face, RTJ a ring type joint. The facing decides the gasket, and ASME B16.20 tabulates the ring joint types separately. MEMO-17 Double block and bleed or double isolation and bleed: which one a spec means 2026-10-03 API describes one valve with two seating surfaces; OSHA describes a procedure using two in-line valves and a bleed. A double block and bleed valve is not required to hold against pressure from one side alone. MEMO-18 WCB, LCB and CF8M: what a valve body material code means 2026-10-07 WCB, LCB and CF8M come from three different ASTM casting specifications. The grade names the material; the valve standard and the material group set the rating. MEMO-19 ASME B16.5 vs B16.47: flange standards compared 2026-10-10 ASME B16.5 is titled NPS 1/2 through NPS 24 and ASME B16.47 NPS 26 through NPS 60. B16.47 is published in two series, and a large diameter line has to name which. MEMO-20 Valve end connections compared: flanged, butt weld, socket or threaded 2026-10-14 ASME B16.34 covers the valve whatever ends it has. B16.5, B16.25 and B16.11 describe the ends. How the four joints compare, and what naming one still leaves open. MEMO-21 Plug valve vs ball valve: which to specify 2026-10-16 Which duty each family takes, what API 599 and API 608 each state they cover, and what naming either one still leaves open on the order. MEMO-22 MSS SP-55: what the visual casting standard covers 2026-10-17 MSS SP-55 judges a casting surface against reference photographs. What it supplements, which MSS practice reaches past the surface, and what naming it still leaves open. MEMO-23 Valve trim: what 13Cr and a hard-faced seat mean 2026-10-18 Trim is the closure member, the seats and the stem. What 13Cr really names, when a seat needs hard facing, and why a trim number on its own instructs nobody. MEMO-24 Handwheel, gearbox or actuator: choosing a valve operator 2026-10-18 The operator is the line of the order that says how the valve is turned. When a handwheel is enough, when it needs a gearbox, and when it has to be actuated. MEMO-25 API 6D vs API 608: which ball valve standard your spec means 2026-10-21 Which document a ball valve line means: what API 6D and API 608 each cover, where API 608 stops, and what the 25th edition of API 6D added. MEMO-26 Bolted bonnet vs pressure seal bonnet: which a valve spec means 2026-10-24 How a bolted bonnet and a pressure seal bonnet seal, the classes each is found in, what API 600 and API 623 say about them, and what a pressure seal valve adds to the order.

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