19-W-4 Hot-Dip Galvanized Steel Bar Grating for Industrial Platform Floor and Trench Drainage

The designation 19-W-4 encodes three key specifications that define the panel's construction and performance:

• 19 — bearing bar spacing in sixteenths of an inch. 19/16 = 1-3/16 in (≈30 mm). For comparison, 15-W-4 is 15/16 in (≈24 mm) and 11-W-4 is 11/16 in (≈17 mm). Closer spacing means more steel and higher cost.
• W — welded construction. Other options are P for pressure-locked and R for riveted.
• 4 — cross bar spacing in inches. For example, 19-W-2 has cross bars every 2 in.

The bearing bar size is expressed as depth × thickness: from 3/4 × 1/8 in for light walkways up to 2-1/2 × 3/16 in for service roads. The panel span — the unsupported distance the bars cross — is the biggest lever on capacity. Going from a 3 ft span to a 5 ft span with the same bar drops allowable load by roughly 60%.

Galvanized weight runs about 6% above mill finish.

Add roughly 6% for hot-dip galvanized panels. A 15-W-4 panel of the same bar is about 18–20% heavier; 19-W-2 is roughly 0.6 lb/ft² (≈2.9 kg/m²) heavier than 19-W-4.

Public NAAMM load tables use an allowable fibre stress of 18,000 psi (ASTM A1011) and list two safe loads: U, uniform load in lb/ft², and C, concentrated load in lb per foot of width. Both are at L/240 deflection — the panel sags 1/240th of its span under the listed load. A 4 ft span sags roughly 0.20 in at L/240; a 6 ft span about 0.30 in. Where the table draws the heavy "exceeds 1/4 in" line, that is the comfort limit, not failure.

Load code ≈50 lb/ft² light industrial. A 1 × 3/16 bar at 4 ft carries around 220 lb/ft² safe uniform load — well above 50. A 1-1/4 × 3/16 bar carries roughly 350 lb/ft²; pick it if a rolling cart is possible.

A 5,000 lb pneumatic-tire forklift puts roughly 7–10 kN on the worst wheel, equivalent to 130–150 lb/ft² uniform load. A 1-1/4 × 3/16 bar drops to ~175 lb/ft² — borderline. A 1-1/2 × 3/16 bar gives ~270 lb/ft² with a 1,300 lb safe concentrated load — the realistic pick. Solid tires add 1.5–2× wheel load; size for that. These figures are indicative — confirm against the supplier's load table.

19-W-4 is the default. Move to 15-W-4 for heel resistance (public walkways), and to 11-W-4 where codes require ≤10 mm aperture. Tighter pitch weighs more and costs more; it does not raise load capacity.

• Bearing bar direction drawn the wrong way — bars must span between supports.
• Metric panel with an imperial load table, or vice versa, without converting.
• "Same as existing" referencing a panel that was undersized when first installed.
• Cut-outs, banding and penetrations priced after galvanizing.