How to use this calculator
- Enter actual pipe geometry. Use outside diameter and wall thickness from the schedule, SDR table or manufacturer drawing.
- Choose material stiffness. Pick a preset or enter custom modulus and density for the pipe material and temperature.
- Add fluid and extra load. Set fluid density, fill percentage and any distributed insulation or jacket load.
- Check the entered span. Compare deflection, bending stress and the governing span against the support spacing you plan to use.
How it works
Pipe support spacing starts with the pipe cross-section. The calculator gets inside diameter from the entered outside diameter and wall thickness: ID = OD - 2t then uses circular tube geometry for area, moment of inertia and section modulus: I = pi(OD^4 - ID^4) / 64 S = I / (OD / 2)
Uniform load is the pipe weight, fluid weight and any entered added distributed load. For a simply supported pipe span, midspan deflection is: delta = 5wL^4 / (384EI) and the bending stress screen is: sigma = (wL^2 / 8) / S The governing support span is the smaller of the deflection-limited span and stress-limited span.
Use the steel pipe schedule chart for steel dimensions, then pair this with pipe size by flow velocity, pipe pressure drop and pipe volume when the same run also needs hydraulic checks. Use the pipe rolling offset calculator before finalizing hangers around a rise-and-roll spool, and the pipe bend developed length calculator when a bent spool controls tangent length and setback.
Worked example
Verified against the live calculator
A steel pipe with 2.375 in OD, 0.154 in wall and
a full water load is checked at a 10 ft support span. With the
steel preset, the calculator builds the pipe ring properties, adds water
weight, then compares the span against L/240 deflection and
the entered allowable bending stress. If the entered span is longer than
the governing span, reduce the spacing or support concentrated loads
separately.
Frequently asked questions
How do I calculate pipe support spacing?
This calculator treats the pipe as a simply supported beam with uniform pipe and fluid weight. It calculates deflection span from delta = 5*w*L^4/(384*E*I), stress span from sigma = w*L^2/(8*S), then uses the smaller span as the governing screen.
Is nominal pipe size enough for hanger spacing?
No. Use actual outside diameter and wall thickness from the pipe schedule, tube drawing, SDR table or manufacturer data. The support-span calculation needs real section properties, not just nominal size.
Can this be used for PVC, HDPE or copper pipe?
Yes as a first-pass mechanics screen if you enter the correct stiffness, density, wall thickness, fluid fill and allowable stress. Plastic pipe often needs temperature and long-term creep-adjusted manufacturer values.
Does this replace plumbing or mechanical code support tables?
No. Final support spacing must follow adopted code, manufacturer support tables and project details. This page only exposes the beam math behind pipe self-weight, fluid weight, deflection and bending stress.
What about valves, insulation and concentrated loads?
Use the extra uniform load field only for loads that are reasonably distributed. Valves, flanges, equipment, anchors, guides and heavy fittings should be supported or checked separately as concentrated loads.
Method & assumptions
- Pipe is modeled as a simply supported circular tube carrying uniform load.
- Pipe weight uses actual OD, wall thickness and material density; fluid weight uses calculated ID, fluid density and fill percentage.
- Deflection span is solved from the entered L/n limit; stress span is solved from the entered allowable bending stress.
- Material presets are stiffness and density shortcuts, not code design values.
- Does not model continuous supports, clamps, guides, anchors, thermal expansion, seismic restraint, vibration, point loads, valves, flanges, fittings, insulation detail, soil/trench support or code-specific hanger tables.