Name: SS Braided Corrugated Hose Assembly
Brand: Essem Works

Braided corrugated hose assemblies across the size range

A braided corrugated hose assembly is a thin-wall stainless tube formed into annular corrugations, sheathed in wire braid and terminated with welded end fittings. It is pressure-tight, it flexes, it takes vibration out of a line, and it survives temperatures that put every non-metallic alternative out of the running. It is the highest-volume product we make.

How it is built, and why that matters

Fig. 1 Anatomy of a braided corrugated hose assembly.

Annular, not helical

Fig. 2 Annular corrugations give the fitting a clean circular seat and produce no torsion under pressure.

Our corrugated hose is annular — each corrugation is a complete ring at right angles to the hose axis, not a continuous screw thread. This is not a cosmetic distinction. A helical profile runs out at the hose end and disturbs the interface where the fitting is attached, and it generates a torsional load when the line is pressurised or takes a pressure shock. Annular corrugations give the fitting an undisturbed circular seat and produce no torsion under pressure. The scope of our ISO 9001 certificate names the product exactly that way.

The corrugation geometry trade-off

Fig. 3 Corrugation geometry. Height and pitch are the two levers and they pull against each other.

Fig. 4 The three profile families and what each buys you.

Profile height and pitch are the two levers, and they pull against each other. Raising the corrugation height and shortening the pitch buys flexibility and costs pressure resistance. Reducing wall thickness does the same. There is no profile that is simultaneously the most flexible and the strongest, so the profile is chosen against the duty rather than sold as a single "best".

Corrugation profile	Wall	Pressure resistance	Flexibility	Typical use
Narrow / undercut	Standard	Lower	Highest	Tight-radius routing, frequent flexing
Standard pitch	Standard	Medium	High	General industrial — the default
Standard pitch	Increased	Highest	Moderate	High pressure, larger bore
Wide pitch	Standard	Medium	Moderate	Cost-sensitive, single-bend installations

What the braid actually does

Fig. 5 The lazy-tongs principle. Crossing angle and length change together.

Fig. 6 Braid restrains the axial extension that pressure would otherwise cause.

The braid is not armour. Its function is to stop the corrugated tube extending axially under internal pressure, and doing so raises the pressure capability of the hose by more than an order of magnitude. It works on a lazy-tongs principle — as the braid is pushed together its crossing angle and diameter increase, and as it is pulled the wires close up and lengthen. A braided assembly can also carry axial tensile load, which an unbraided hose cannot.

Braid arrangement	Construction	Where we use it
Single braid	One layer over the hose	Standard duty across most of the range
Double braid	Two layers	Higher pressure at the same bore
Knurled braid	Wires within each carrier braided together	Larger nominal diameters, where wire cross-section per carrier must increase
No braid	Bare corrugated hose	Low pressure, vacuum, or where the hose is a conduit rather than a pressure part

We do not offer triple braid. A third layer adds very little pressure capability and takes away a great deal of flexibility. Where a customer is reaching for triple braid, the right answer is almost always a heavier wall or a larger bore.

Fig. 7 The two forming routes. Which one we use follows from bore and wall thickness.

Fig. 8 Braid arrangements and what each one is for.

Working pressure and bend radius

This is the table most people come here for. Sizes run DN6 to DN350, and every column below — working pressure, hydrostatic test pressure, static radius and both flexing radii — comes straight from Essem's own technical data, not a derived or rounded figure. Pressures are in kg/cm² at

All 8 figures — Max WP and Test Pressure for each braid type, plus the three bend radii — are in the table below. If your screen is narrow, scroll the table sideways to see every column, including Test Pressure.

20 °C for a complete braided assembly with welded end fittings — apply the derating factors below for anything hotter.

Max WP and Test Pressure are in kg/cm²; all bend-radius figures are in mm. Nominal size in mm corresponds directly to DN (e.g. 50 mm = DN50). The above values apply to Essem Works braided corrugated hoses and assemblies. Pressure ratings are for fluid and ambient temperature of 20 °C — for higher temperatures apply the correction factor from the temperature-derating table below. 14" (DN350) supplied on request — confirm ratings with us. Source: EWPL Technical Data (final), August 2026.
Nominal Size		Without Braid		Single Braid		Double Braid		Min Bend Radius
Inch	mm	Max WP	Test Pressure	Max WP	Test Pressure	Max WP	Test Pressure	Static	Flexing Type-1	Flexing Type-2
1/4	6	4	6	100	150	160	240	25	110	140
5/16	8	4	6	100	150	160	240	32	130	165
3/8	10	4	6	90	135	144	216	38	150	190
1/2	12	3	4.5	80	120	128	192	45	165	210
5/8	16	3	4.5	70	105	112	168	58	195	250
3/4	20	2	3	64	96	102	153	70	225	285
1	25	2	3	50	75	80	120	85	260	325
1 1/4	32	1.5	2.3	40	60	64	96	105	300	380
1 1/2	40	1.5	2.3	30	45	48	72	130	340	430
2	50	1	1.5	28	42	44	66	160	390	490
2 1/2	65	1	1.5	24	36	38	57	200	460	580
3	80	1	1.5	18	27	28	42	240	600	800
4	100	0.8	1.2	16	24	26	39	290	750	1000
5	125	0.6	0.9	12	18	20	30	350	1000	1250
6	150	0.6	0.9	10	15	16	24	400	1250	1550
8	200	0.5	0.75	8	12	12	18	520	1600	2000
10	250	0.25	0.36	6	9	9	14	620	2000	2500
12	300	0.2	0.3	4	6	6	9	720	2400	3000
14 *	350	0.1	0.15	2	3	4	6	900	3000	3600

Four things to read alongside that table

Unbraided hose is not a low-cost braided hose. We supply it as bulk hose for customers who fabricate their own assemblies, and for low-pressure drain and vent duty. It is limited by convolution squirm. Never run it at braided-assembly pressures. If you fabricate your own ends, the attachment, the testing and the rating are yours.

Static and flexing bend radius are different columns for a reason. Static is a permanently formed installation bend. The two flexing columns, Type-1 and Type-2, are both for repeated movement — tell us the cycles and the amplitude your duty needs and we will confirm which one applies; Type-2 is the figure to use if you cannot get that information from us before you have to design the routing. Type-2 runs from about three times the static figure at the large end to five and a half times at the small end. Use the flexing figure whenever the hose moves, and read the number rather than applying a ratio.

For pulsating or surge service, halve the working pressure.

The fitting can limit the assembly. Fitting type, material and attachment method all cap the rating at temperature, sometimes below the hose itself.

The pressure basis we publish to

Two ratios govern every pressure figure on this site, and we hold both:

Burst pressure is at least four times working pressure. A safety factor of four is the accepted basis for corrugated metal hose and it is what ISO 10380 assumes.
Test pressure is 1.5 times working pressure. Every pressure-retaining assembly is hydrostatically tested before despatch.
Every published rating is an ambient-temperature figure, taken at 20 to 23 °C. Hot lines take the derating factor from the table below; it is not optional and it is not small.

Static rating and moving rating are different numbers. The permissible pressure for a hose sitting still is higher than the rating for the same hose while it is being flexed, because movement introduces a localised buckling risk that a static installation does not have. Where a hose will move in service, specify against the moving figure.

Temperature

Standard service for the stocked grades is −196 °C to +450 °C. Between 450 and 550 °C we derate and review the application with you. Above 550 °C the answer is SS 321 or Alloy 625 (UNS N06625), built to order.

Multiply the working pressure by the factor. Proof-stress basis to ISO 10380 — the ratio of 1 % proof stress at temperature to proof stress at 20 °C. 904L is rated to 400 °C; above that the answer is 321 or Alloy 625 (UNS N06625).
Medium temperature	SS 304L	SS 316L	SS 321 (to order)	SS 904L (to order)
20 °C	1.00	1.00	1.00	1.00
100 °C	0.72	0.74	0.83	0.87
200 °C	0.59	0.62	0.74	0.76
300 °C	0.51	0.54	0.67	0.65
400 °C	0.46	0.50	0.62	0.57
450 °C	0.45	0.48	0.61	—
500 °C	0.44	0.47	0.60	—
550 °C	0.43	0.47	0.59	—

Worked example. A DN50 single-braid assembly is rated 28 kg/cm² at 20 °C. At 300 °C in 316L the factor is 0.54, so the assembly is good for 28 × 0.54 = 15.1 kg/cm². If your line runs at 20 kg/cm² hot, this assembly does not do the job — move to double braid, which is 44 kg/cm² cold and 23.8 kg/cm² at 300 °C. The derating calculator does this for you.

Bend radius — three numbers, not one

A single "minimum bend radius" figure is close to meaningless unless the duty is stated with it. We publish three, because they describe different things.

Static bend radius — a permanently formed installation bend, made once and left alone.
Dynamic (flexing) bend radius, Type-1 and Type-2 — the radius to design to where the hose flexes in service. Both are for repeated movement; which one your duty needs depends on the cycles and amplitude, so tell us and we will confirm it. Type-2, the larger of the two, runs roughly 2.9 to 5.6 times the static figure across our range, depending on size.

Installing to the static radius and then flexing the hose is one of the most common causes of premature failure we are asked to investigate. Bend radius and live length sets out the calculation.

Braid detail — the wires that carry the pressure thrust

Materials

The hose wall is formed from cold-rolled strip, welded longitudinally and then corrugated, so the material has to take a great deal of cold work without cracking. That requirement rules a lot of alloys out and is why austenitic stainless dominates.

Component	Standard material	Alternatives on request
Corrugated hose	SS 316L (1.4404)	SS 304L (1.4307), SS 321 (1.4541), 904L, Alloy 625 (UNS N06625), Alloy 825 (UNS N08825)
Wire braid	SS 304 (1.4301)	SS 316L where the braid is exposed to the same medium or atmosphere as the bore
End fittings	SS 304 / SS 316L	Carbon steel, duplex, or to customer specification

Full composition and cross-standard designations are on material grades.

What we need from you to quote

Seven pieces of information turn an enquiry into a specified assembly. They are set out in full, with the reasoning behind each, in how to specify an assembly.

Bore sizeTemperature — medium and ambientApplication and movementMedium and concentrationWorking pressureEnd connectionsDynamics — flexing frequency and amplitude

SS Braided Corrugated Hose Assemblies