What a strut-channel pipe support is made of

A strut trapeze is five layers: beam clamp, rod, cross channel, channel nuts, pipe clamp. We quote the complete set: beam clamp, rod, channel, nuts and pipe clamp. The rod layer is supplied to order as part of the set — fully threaded rod, rod coupling, and hex nut, 3/8–3/4 in. and M10–M20. Not a catalog part number; quoted as commodity hardware with the set. Where a part on this page takes rod outside that range (J1280, J1280N, M30, and M31), that rod is confirmed at quotation. Clevis hangers and rod eye nuts are not in the catalog pages this site draws on; if your design uses them, list them in the inquiry and they are confirmed at quotation.

This page names the part numbers in each layer and gives the catalog page every one of them is printed on. It is a parts list, not a design. There is not a single load figure on this page — the published ratings live on Clamps and Nuts, and the span tables on Channel. Read them there, where the safety factor is printed beside the number.

Jump to a layer: beam clamps · rod · cross channel · the catalog’s trapeze selection · nuts · pipe clamps · rollers and brackets

Getting the set

1 · Beam clamp

Grips the flange of the structural steel, so nothing has to be drilled or welded. We quote this.

2 · Rod

Carries the cross member down to working height. Supplied to order as part of the set — fully threaded rod, rod coupling and hex nut; sizes below.

3 · Cross channel

The horizontal member the pipes sit on. We quote this.

4 · Channel nuts

Turn into the channel and take the bolt, anywhere along the run. We quote this.

5 · Pipe clamp

Holds the pipe to the channel. Picked from the pipe’s outside diameter, not its trade size. We quote this.

The catalog describes the role of the section as a whole: “Unistrut pipe clamps, pipe hangers, brackets and rollers are designed for the support of electrical and mechanical services.” It names no industry and no building type, and neither do we. Source: Unistrut® General Engineering Catalog no. 17, p. 137 · Verified 2026-09-19

The five layers

1 · Getting onto the structural steel

One of these takes channel directly; the rest take a rod. That is the first fork.

2 · The rod layer, supplied with the set

The rod layer is supplied to order as part of the set: fully threaded rod, rod coupling, and hex nut, in 3/8–3/4 in. and M10–M20. Not a catalog part number; quoted as commodity hardware with the set — catalog no. 17 prints no number for it, so the rod is specified by diameter, thread and length on the quotation rather than by a P number. Where a part on this page takes rod outside that range (J1280, J1280N, M30, and M31), that rod is confirmed at quotation; those sizes are marked ‡ in the tables below.

Clevis hangers and rod eye nuts are not in the catalog pages this site draws on; if your design uses them, list them in the inquiry and they are confirmed at quotation. What catalog no. 17 does have here is a one-piece rod-suspended hanger that clamps the pipe itself, and two ceiling flanges that receive the rod.

Rod supply — the three items and both size ranges — is our supply, not a catalog figure, and the exact diameter, thread and length are confirmed at quotation.

At the ceiling end, M30 and M31 swivel ceiling flanges receive the rod; the table gives the mounting bolt, the hole and the rod sizes each one takes. The rod between them and the hanger comes with the set, on the terms above.

3 · Choosing the cross channel

Geometry only below. Which section a given run needs is a span question, and the span tables are on the channel page.

The catalog’s own trapeze selection, for sprinkler pipe

For one case the catalog does the selection itself: a trapeze carrying sprinkler pipe. It prints which channel to use for a given span and pipe size. The tables are reproduced here as selections only; they are not a rating for any other load.

Four tables: single-channel and double-channel trapeze, each for Schedule 10 and Schedule 40 pipe. Rows are trapeze spans, columns nominal pipe diameters; each cell is the channel the catalog selects for that pair. The single-channel tables use P1000, P3000, P5000, and P5500; the double-channel tables use P1001, P3001, P5001, and P5501, all back-to-back. The two double-channel tables print the same selection cell for cell.

N/A is the catalog’s own entry; its note reads “An entry of ‘–’ indicates that the channel cannot be used for this span/pipe size combination.”, and the tables print it as N/A. The selections are, in the catalog’s words, “Based on NFPA-13-1996 Section Modulus Table 3-10.1.7(a).” The loading assumptions stated in the same note, and the section-modulus tables printed beside the selections, are design values and are not reproduced here. Spans in millimeters are computed from the printed feet and inches (1 in. = 25.4 mm) and marked ≈; pipe diameters are nominal sizes. The pages are headed “Channel Selection for Schedule 10 Sprinkler Pipe Trapeze Hangers” and “Channel Selection for Schedule 40 Sprinkler Pipe Trapeze Hangers”. Source: Unistrut® General Engineering Catalog no. 17, p. 156–157 · Verified 2026-09-28

4 · Matching the channel nut to the channel

The families split by how deep the channel is. Getting this wrong is the most common way a trapeze will not go together on site.

5 · Clamping the pipe

Pick by the pipe’s outside diameter, never by the trade size on the drawing — that is the whole reason there are two series.

Rollers and brackets, where the pipe has to move

A long run that grows and shrinks needs a roller rather than a clamp. These are the catalog’s, in the same section, with the dimension that decides which one fits.

Dimension “A” is chosen from the pipe size and the insulation thickness, not printed as one figure per part. An empty cell is empty on the chart; * is the catalog’s own “Not used for this size”. P2476 has no “No Insulation” or “1 in.” column. Insulation thicknesses in millimeters are as the p. 151 chart header prints them; p. 150 and p. 152 print inches only. Pipe sizes are nominal. Source: Unistrut® General Engineering Catalog no. 17, p. 150–152 · Verified 2026-09-28

The same section also prints two pipe support brackets, drawn on an upright channel, and a pipe block.

Joining the cross members

Where two channels meet, the joint is a fitting; the post bases are for where the support stands on the floor instead of hanging.

Matching table & suffixes

Channel, nut and clamp: which part number goes with which

One table for the three-way match. Read along the row you are building.

The nut columns are the “For Use With Channel” charts on p. 78–79, which list single channels only, so a back-to-back combination has no entry there. The P2784 column is the “For Use With” column of its table on p. 122; “Not listed” means the catalog lists no variant for that series, not that we did not look. P3001, P3301, P4001, and P4101 appear in neither and are left out. Threads for each nut family are in the nut table above; depth is the catalog figure from each series page. Source: Unistrut® General Engineering Catalog no. 17, p. 78–79 (nuts), p. 122 (P2784), p. 25, 32, 36, 40, 43, 46, 50, 53, and 56 (depths) · Verified 2026-09-28

The suffix rules

A part number carries up to three suffixes, from three different systems, and one system’s letters do not carry over to another.

What we do not publish

What we do not publish, and what we can arrange instead

There is no load figure on this page, and that is a position rather than an omission. The catalog publishes its design load data under conditions it prints itself: “All parts drawings illustrate only one application of each fitting. In most cases many other applications are possible”, and design load data “is based on the ultimate strength of the connection” with a stated safety factor, “unless otherwise noted” (p. 85) — and the pipe and conduit supports section states its own, different factor on p. 137. The fitting tables on p. 89 are tighter still: they hold only “when used in position shown”, with both ends of the beam supported, and with a P1010 nut and a 1/2 in. bolt.

So a printed rating is a number for one reference part, in one drawn position, with one nut and one bolt. A trapeze is a whole assembly with a span, a connection detail and a load path, and its capacity is not the smallest number on its parts list. On top of that, what we quote is a candidate substitute made to order against the catalog number, which means the reference part’s published figures are not ours to repeat.

What we can do instead, when a submittal needs numbers: tell us the span and the connection detail, and we price the evidence rather than assert it — measured coating thickness, mill certificate, and a third-party load test on the actual parts, arranged per order and confirmed at quotation. Until that test exists we publish nothing, which is why the catalog figures on our clamp and nut pages are labeled as the catalog’s throughout.

Conditions quoted from Unistrut® General Engineering Catalog no. 17, p. 85, 89 and 137. The candidate-substitute position and the list of tests not yet run are our own · Verified 2026-09-28

What we cannot quote for this assembly

• Clevis hangers and rod eye nuts. Not in the catalog pages this site draws on; list them in the inquiry and they are confirmed at quotation. Threaded rod, rod couplings and hex nuts are a separate case: they are supplied with the set as commodity hardware, not as catalog part numbers.
• Nothing engineered. These are catalog tables; sizing a support is a design decision for your engineer, and no figure on this site is a design.
• No listed-assembly claim. Approvals belong to the manufacturer that obtained them and do not travel with a part number.
• No insulation, saddle or shield. The catalog says the saddle is by others, and so do we.

Quote

Where to go next

• Clamps — the same part numbers with their published loads, outside diameters and gauges.
• Channel span versus load — what a given cross member will actually carry.
• Finishes — and the pipe-clamp material suffixes, which are their own system.
• 41 mm metric strut channel — if the drawing calls the cross member 41x41.

Frequently asked questions

Trademarks and who we are

Unistrut, B-Line, Superstrut, Power-Strut and Haydon, and the part numbers published under them, are trademarks or trade names of their respective owners. ChannelStrut is not affiliated with, authorized by, endorsed by or a distributor for any of them. Those brand names and part numbers are used here only to identify the products referred to.

ChannelStrut is run by Alex, a hardware sourcing specialist based in Fujian, China. We do not manufacture these parts — we source them from the mills that produce them. More on how the data is built: About.