P4004 - 1-5/8" x 3-1/4", 16 Gage, Quadruple Combination

Unistrut's P4004 (quadruple combination), often known as 16 gauge standard or deep back-to-back strut channel, is commonly used for electrical supports, mechanical supports, pipe, conduit, duct and cable tray supports, and other general framing. For application examples, refer to our Application Showcase

This channel is ideal because it provides additional loading capacity and multiple connection points on a single plane versus a double or triple combination.

Product dimensions are 1 5/8" long x 3 1/4" wide x 16 ga. thick; quadruple combination. 

Our P4004 is available in the following finishes: Pre-Galvanized (PG), Hot-Dip Galvanized (HG), Plain (PL), Green (GR), Zinc Dichromate (ZD) and Stainless Steel (SS).

Part No. Length (ft) Finish Product Weight / Ft (lbs/ft)
P4004 10 PG 3.31
P4004 20 PG 3.31
P4004 20 GR 3.31
P4004 10 GR 3.31
P4004 20 PL 3.31
P4004 10 PL 3.31
P4004 20 SS 3.31

    Elements of Section

    Elements of Section - P4004
    Area of Section 0.974 in2 (6.3 cm2)
    Axis 1-1 Axix 2-2
    Moment of Inertia (I) 0.882 in4 (36.7 cm4) 0.287 in4 (11.9 cm4)
    Section Modulus (S) 0.543 in3 (8.9 cm3) 0.353 in3 (5.8 cm3)
    Radius of Gyration (r) 0.952 in (2.4 cm) 0.543 in (1.4 cm)

    General Specifications

    Standard Lengths:

    • 10 feet:  10' or 10’ 1/8” (3.05m) ± 1/8" (3 mm)
    • 20 feet:  20' or 20’ 3/8” (6.11m) ± 1/8" (3 mm)

    Special Lengths:

    Curved Channel:

    • Many Unistrut channel sections can be supplied with a curve. Click here for our ordering form, specifications, and instructions.

    Load Data:


    • All beam and column load data pertains to carbon steel and stainless steel channels.
    • Load tables apply only to UNISTRUT brand channel. Look for "UNISTRUT" on the product.
    • Load tables and charts are constructed to be in accordance with the SPECIFICATION FOR THE DESIGN OF COLD-FORMED STEEL STRUCTURAL MEMBERS 2007 EDITION published by the AMERICAN IRON AND STEEL INSTITUTE USING ASD METHOD.
    • Loads are based on 33 ksi steel cold formed to 42 ksi.
    • Safety Factor to Yield Strength is 1.67 for Beam Loads and 1.80 for Column Loads.
    • Beam loads are based on a simple beam and are given as a total uniform load (W) in pounds. For proper calculation procedures, refer to our Beam Load Calculation Guide.
    • For bearing loads, reference our bearing loads page.


    • Welded channels are spot welded 2" (51 mm) or 3" (76 mm) on-center. 



    Materials & Finishes

    Materials & Finishes - Standard:

    • Pregalvanized (PG):  Conforms to ASTM A653 SS GR 33, G90.
    • Unistrut Defender (DF):  Conforms to ASTM A1046 SS GR 33
    • Hot Dip Galvanized (HG):  Steel conforms to ASTM A1011 SS GR 33, Finish conforms to ASTM A123
    • Perma-Green (GR):  Steel conforms to ASTM A1011 SS GR 33, E-Coat finish
    • Perma-Gold (ZD):  Steel conforms to ASTM A1011 SS GR 33, Finish conforms to ASTM B633, Type II SC3
    • Plain (PL):  Conforms to ASTM A1011 SS GR 33
    Materials & Finishes - Special Metals:
    • Stainless Steel, Type 304 (SS):  ASTM A240, Type 304 *
    • Stainless Steel, Type 316 (ST):  ASTM A240, Type 316 *
    • Aluminum (EA):  ASTM B221, Type 6063-T6 (Extruded) *

    * These materials have different physical properties and performance characteristics. Please contact us for design support.