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Inzonex Modular Insulation · Hot-water skid
Every joint is a fin the pipe did not ask for. Drag the divider: the right-hand side is a fitted removable module on this exact geometry.
Estimate: 18 × 0.192 m² · 60 °C bare surface · 8,000 operating hours/year.
For your operating conditions
Change any input and every figure recomputes. The defaults describe the equipment modelled here.
What this is
Every joint is a fin the pipe did not ask for.
A flange is a flat collar on the end of a pipe or fitting. It bolts face to face against a matching collar with a gasket between them, so the joint comes undone without cutting the pipe.
On this hot-water skid there are 18, each about 0.1921 m² of surface above room temperature. At 60 °C they shed 1.9 kW into the plant room. With 50 mm of removable insulation the same surfaces shed 101 W, 94.6 % less. The module settles at 23.5 °C, at or under our 45 °C touch-safe target. We set that target against the burn thresholds in EN ISO 13732-1.
These are steady-state model estimates using the stated areas and class assumptions. Agreement with site measurements or a survey report has not been established.
Inzonex benefits
Flanged joints on the hot-water skid: pump suction and discharge, exchanger ports, valve pairs and the meter run. Made to EN 1092-1 PN16 on this circuit. Modules unclip for operation and inspection, then refit onto the same geometry.
European plant is dimensioned to EN 1092-1 by nominal pressure — PN6, PN10, PN16, PN25. North American plant uses ASME B16.5 classes 150, 300, 600. The bolt circle and the raised face differ, so a PN16 flange and a class-150 flange of the same DN do not mate.
Weld-neck carries the load into the pipe and is what you find on a plant-room header. Slip-on is quicker to fit and weaker in fatigue. Blind closes a branch kept for future use — and a blind flange on a live header is a hot plate with nothing behind it.
A joint is broken to change a gasket, to lift a pump or to rod a strainer. Bolts need a socket square on the nut, so a cover that has to be cut to reach them is cut once and never refitted.
Gasket relaxation after the first heat cycle is the usual cause. Joints get re-torqued warm. A weeping flange under fixed lagging soaks the insulation and starts corrosion under it, unseen.
Area and temperature scenarios
Bare surface loss per item. Nothing here is interpolated — each cell is a separate solution of the same balance, at 20 °C ambient.
| Reference scenario | Area m² | 50 °C | 55 °C | 60 °C | 65 °C | Insulated 60 °C | Cut |
|---|---|---|---|---|---|---|---|
| Area scenario 1Not a product size | 0.1115 | 42 W | 51 W | 60 W | 69 W | 3 W | 94.6 % |
| Area scenario 2Not a product size | 0.1249 | 47 W | 57 W | 67 W | 78 W | 4 W | 94.6 % |
| Area scenario 3Not a product size | 0.1434 | 54 W | 65 W | 77 W | 89 W | 4 W | 94.6 % |
| Area scenario 4Not a product size | 0.1709 | 65 W | 78 W | 92 W | 106 W | 5 W | 94.6 % |
| Area scenario 5Not a product size | 0.1921 | 73 W | 88 W | 103 W | 119 W | 6 W | 94.6 % |
| Area scenario 6Not a product size | 0.2388 | 90 W | 109 W | 128 W | 148 W | 7 W | 94.6 % |
| Area scenario 7Not a product size | 0.2954 | 112 W | 135 W | 159 W | 183 W | 9 W | 94.6 % |
| Area scenario 8Not a product size | 0.3769 | 143 W | 172 W | 202 W | 234 W | 11 W | 94.6 % |
| Area scenario 9Not a product size | 0.5315 | 201 W | 242 W | 285 W | 330 W | 15 W | 94.6 % |
| Area scenario 10Not a product size | 0.7160 | 271 W | 327 W | 384 W | 444 W | 21 W | 94.6 % |
| Area scenario 11Not a product size | 0.9595 | 363 W | 438 W | 515 W | 596 W | 28 W | 94.6 % |
| Area scenario 12Not a product size | 1.49 | 562 W | 678 W | 798 W | 922 W | 43 W | 94.6 % |
Illustrative areas, not verified DN-to-area mappings for this equipment. Replace the input with measured external geometry for a project calculation. Physical bolt, nut, flange and stem coverage must be checked separately.
Insulated column: 50 mm lamella at λ 0.038 W/m·K. Outer surface calculated without clamping. Our 45 °C design target is checked against the burn thresholds in EN ISO 13732-1
What this means
At the modelled defaults, on this equipment.
Asked about flanged joints
Answers distinguish modelled heat-loss estimates from equipment selection and service guidance.
A flat collar on the end of a pipe, bolted against a matching collar with a gasket between them. It is what lets a pump, a valve or a heat exchanger be removed without cutting pipework. It is also the thickest ring of metal on the run, and it loses heat out of proportion to its length.
Weld-neck has a tapered hub welded to the pipe and carries bending load, which is what a plant-room header needs. Slip-on sits over the pipe and is fillet-welded both sides — quicker, weaker in fatigue. Blind has no bore and closes a spare branch. Threaded and lap-joint appear on smaller and on lined systems.
PN is the European series in EN 1092-1, rated by nominal pressure in bar — PN6, PN10, PN16, PN25, PN40. ANSI, properly ASME B16.5, is rated by class — 150, 300, 600. The two use different bolt circles and different numbers of bolts. A PN16 and a class-150 flange of the same DN will not bolt together. They are not interchangeable and there is no adaptor: you change the flange.
The flange follows the pipe, not the other way round. DN is the nominal bore of the pipe it terminates, and the pressure rating follows the system. So a DN50 PN16 pipe takes a DN50 PN16 flange. Outside diameter, bolt circle and bolt count then come from the table in EN 1092-1 for that combination.
Nearly always the gasket. It relaxes after the first heat cycle. Joints on a new circuit are re-torqued warm. After that the usual causes are uneven bolt-up, a face damaged during assembly, or a gasket left in past its service life. Under fixed lagging a weep is invisible: it soaks the insulation, and corrosion under insulation starts there.
Modelled here: 18 joints of 0.1921 m² at 60 °C lose 1.9 kW bare and 101 W with 50 mm — 94.6 per cent less. The figure covers both faces and the bolting. One joint loses more than the half-metre of pipe on either side.
What the numbers mean
Steady-state estimate using convection, radiation and an insulation energy balance. Equivalence to a surveyed equipment model has not been established.
Going deeper
The figures on this page say what the heat costs. These say which type to order, which standard it has to match, and why the joint is weeping.
Five types cover almost everything in a plant room, and they are not interchangeable.
OpenFlanged jointsTwo flanges of the same bore, from two standards, will not meet.
OpenFlanged jointsThe metal does not seal. The gasket does, and it is the part with a life.
OpenThe rest of the skid
A plate pack runs hot on every face.
OpenHot waterThe casing stays hot. The motor must not.
OpenHot waterThe smallest surfaces lose the most.
OpenHot waterA sieve in the line, and it is opened on a cycle.
OpenHot waterA separator holds its charge at line temperature.
Open