What the W10x19 Designation Means
W10x19 is a wide flange beam from the ASTM w shape series, the profile that most of the world calls an H-beam or universal beam. The letter W identifies a hot rolled wide flange section, the number 10 is the nominal depth in inches, and the number 19 is the nominal weight in pounds per foot.
Because the designation is nominal, the real dimensions never match the title exactly. A W10x19 is 10.24 inches deep, not 10 inches, and it weighs 19 pounds per foot, which converts to about 28.3 kg per metre. Metric drawings of the same member usually quote a depth of 260 mm and a mass of 28.3 kg/m.
Nominal Dimensions and Unit Weight
The values below are the nominal dimensions of the W10x19 profile, rounded to the precision used in design tables. Depth, flange width and thicknesses are controlled by the dimensional tolerances of ASTM A6.
| Dimension | Imperial | Metric |
|---|---|---|
| Depth, d | 10.24 in | 260 mm |
| Flange width, bf | 4.020 in | 102 mm |
| Web thickness, tw | 0.252 in | 6.4 mm |
| Flange thickness, tf | 0.311 in | 7.9 mm |
| Unit weight | 19 lb/ft | 28.3 kg/m |
| Cross sectional area | 5.62 in2 | 36.3 cm2 |
Two features stand out. The web is relatively thin compared with the flanges, which keeps the member light for its bending capacity, and the section is compact for its depth, so it can be used where headroom is limited and a shallow, stiff beam is needed.
Section Properties and Structural Behaviour
Section properties govern how the beam performs, and they should always be taken from the shape tables for the exact profile rather than estimated from the nominal designation.
| Property | Imperial | Metric |
|---|---|---|
| Moment of inertia, Ix | 96.0 in4 | 4000 cm4 |
| Elastic section modulus, Sx | 18.8 in3 | 308 cm3 |
| Radius of gyration, rx | 4.14 in | 105 mm |
| Moment of inertia, Iy | 4.29 in4 | 179 cm4 |
| Elastic section modulus, Sy | 2.14 in3 | 35.1 cm3 |
| Radius of gyration, ry | 0.874 in | 22.2 mm |
The wide flange shape concentrates material in the flanges, so bending about the strong axis is efficient. The weak axis properties are small, as the low ry value shows, which means the member needs lateral restraint in compression zones and should be braced by decking, purlins or a diagonal system when it acts as a beam or a column.
Material Grades, Tolerances and Availability
W shapes are normally rolled in ASTM A992, a steel developed specifically for wide flange beams, with a minimum yield strength of 345 MPa and a minimum tensile strength of 450 MPa. ASTM A572 Grade 50 offers the same nominal strength with different chemistry limits, and A36 remains available in some sizes for older designs. Equivalent hot rolled sections in the EN system, such as an HEB or IPE profile of similar depth, are often substituted when a metric project is converted.
Dimensional tolerances follow ASTM A6, which covers depth, flange width, out-of-square, camber and straightness. Mill certificates confirm the heat number, chemistry and mechanical test results for each cast, and third party inspection can be arranged against the project specification when the structure is safety critical.
Fabrication, Connections and Protection
The W10x19 is readily cut with a band saw or abrasive disc, and it is easily drilled or punched for bolted connections. Because the web is thin, hole positions should be checked against the minimum edge and end distances of the applicable code, and weld sizes on the web should be limited to what the section can accept without excessive distortion.
Typical connection details include shear tabs welded to the web, end plates welded to the section profile, and simple bolted cleats. Where the beam supports a concrete slab, shear studs are welded through the deck or directly to the top flange. Corrosion protection for a hot rolled member normally consists of blast cleaning to the specified surface preparation grade followed by a zinc-rich primer or, for exposed or wet service, hot dip galvanizing.
Typical applications include floor and roof beams in industrial buildings and warehouses, mezzanine framing, monorail and crane supports, pipe racks, machine bases, platform framing and small to medium span bridge stringers.
FAQ
Q: What is the actual depth of a W10x19?
Structurally it is 10.24 inches, or 260 mm. The 10 in the designation is a nominal size label, and a W10x19 is not the same depth as every other section in the W10 group.
Q: How much does a W10x19 weigh per metre?
The nominal weight is 19 pounds per foot, which is about 28.3 kg per metre. The actual mill weight can differ slightly within the tolerances of ASTM A6.
Q: What steel grade is used for W10x19 beams?
ASTM A992 is the standard grade, with a minimum yield strength of 345 MPa and a minimum tensile strength of 450 MPa. ASTM A572 Grade 50 and, for older work, ASTM A36 are also seen.
Q: Can a W10x19 be used as a column?
Yes, but its weak axis radius of gyration is only about 22 mm, so the unbraced length is usually controlled by buckling about the minor axis, and the capacity should be checked accordingly.
Q: What is the metric equivalent of a W10x19?
There is no exact equivalent. An HEA, HEB or IPE profile of about 260 mm depth is often used as a substitute, but the section properties differ and the design must be re-checked rather than swapped by depth alone.