Fiberglass Grating Load Tables: Span, Load & Deflection

A fiberglass grating load table lists, for each clear span, the deflection a panel shows under uniform loads (psf) and line loads (lb per foot of width). Find your span, read the deflection at your load, and check it against your limit, often 3/8" (9.5 mm) or L/120. Strongrate's catalog tables for each product are indexed below.

Which load tables does Strongrate’s catalog include?

The 2023 catalog prints 27 deflection tables: uniform, line and point loads for seven molded mesh families, and uniform and line loads for three pultruded series. Each product page shows the rows for its depths or types.

Molded grating load tables in Strongrate’s 2023 catalog, by mesh (catalog pages)

Mesh family	Depths printed	Uniform load	Line load	Point load	Product page
1-1/2" × 1-1/2" (38 × 38 mm) square	3/4", 1", 1-3/16", 1-1/2", 2-3/8" (20, 25, 30, 38, 60 mm)¹	p. 56¹	p. 55¹	pp. 56–57¹	1-1/2" molded grating
1-9/16" × 1-9/16" (40 × 40 mm) square	1", 1-3/16", 1-9/16" (25, 30, 40 mm)¹	p. 58¹	pp. 57–58¹	pp. 58–59¹	Molded fiberglass grating
2" × 2" (51 × 51 mm) square	1-9/16", 2" (40, 50 mm)¹	p. 60¹	p. 59¹	pp. 60–61¹	2" molded grating
1" × 3-15/16" (25 × 100 mm) rectangular	1", 1-3/16", 1-1/2" (25, 30, 38 mm)¹	pp. 61–62¹	p. 61¹	pp. 62–63¹	Rectangular mesh grating
Other rectangular (slot) meshes, including 1" × 6" (25 × 152 mm)	1-1/8", 1-1/2", 1-9/16", 2" (28, 38, 40, 50 mm)¹	pp. 64–65¹	pp. 63–64¹	pp. 65–66¹	Rectangular mesh grating
Mini mesh and micro mesh	1", 1-3/16", 1-1/2", 1-9/16", 2" (25, 30, 38, 40, 50 mm)¹	pp. 67–68¹	pp. 66–67¹	pp. 68–69¹	Mini-mesh ADA grating
HLC heavy-load meshes	1", 2", 2-3/8" (25, 50, 60 mm)¹	pp. 70–71¹	pp. 69–70¹	p. 71¹	Trench covers and drain grates

Depths are the nominal inch sizes of the printed metric depths.

Notes

1Deflections as printed in the factory catalog (2023), static loads at ambient temperature; confirm for your span in the submittal before final design.

Pultruded grating load tables in Strongrate’s 2023 catalog, by series (catalog pages)

Series	Types printed	Uniform load	Line load	Product page
I-bar, 1" types	I-4010, I-5010, I-6010¹	p. 73¹	p. 72¹	1" I-bar grating
I-bar, 1-1/2" types	I-4015, I-5015, I-6015¹	p. 73¹	p. 72¹	1-1/2" I-bar grating
T-bar	T-1210, T-2510, T-3310, T-3810, T-1215, T-2515, T-3815, T-1810, T-3320, T-5020¹	pp. 74–75¹	pp. 73–74¹	2" T-bar grating
HL and HI high-load I-bar	HL-4020, HL-5020, HL-6020, HI-4710, HI-4715, HI-4720, HI-4725, HI-4730¹	p. 77¹	p. 76¹	Pultruded fiberglass grating

The catalog prints no point-load tables for pultruded grating.

Notes

1Deflections as printed in the factory catalog (2023), static loads at ambient temperature; confirm for your span in the submittal before final design.

How do you read Strongrate’s catalog load tables?

Each row is a clear span; each column is an applied load (uniform in psf, line in lb per foot of width, point in lb), with the catalog’s metric value in parentheses. Cells are deflection in inches with the printed millimeters; a dash means no value is printed. The “Max load” column is not defined in the catalog, so do not read it as a safe or allowable load.

Notes printed with Strongrate’s catalog load tables

Item	What the catalog says
Deflection limit for worker comfort	The lesser of 3/8" (10 mm) or L/125¹
Deflection limit for a firmer feel	The lesser of 1/4" (6.4 mm) or L/200¹
Load conditions	Static loads at ambient temperature only¹
Impact or dynamic loads	At most half the tabulated loads¹
Long-term loads and heat	Long-term loads add creep deflection and need higher safety factors; consult the factory for elevated temperatures¹
Test basis	Tested to the ANSI/ACMA FRP Composites Grating Manual for pultruded and molded grating and stair treads¹

L is the clear span. The catalog’s comfort limit uses L/125, slightly stricter than the L/120 in US guide specifications.

Notes

1Catalog tables; confirm the values for your span in the submittal before final design.

The project engineer sets the deflection criterion.

Worked example from the table below: for 1-1/2" (38 mm) deep molded grating with a 1-1/2" × 1-1/2" (38 × 38 mm) mesh at a 23-5/8" (600 mm) clear span, the catalog prints a deflection of 0.05" (1.22 mm) under 102 psf (500 kg/m²). The firmer-feel limit at that span is L/200, or 0.12" (3 mm), so that value is inside both catalog limits.

Uniform load deflection, Strongrate molded grating, 38 × 38 mm mesh (catalog page 56)

Clear span	Depth	31 psf (150 kg/m²)	72 psf (350 kg/m²)	102 psf (500 kg/m²)	154 psf (750 kg/m²)	205 psf (1,000 kg/m²)	307 psf (1,500 kg/m²)	512 psf (2,500 kg/m²)	Max load, psf (kg/m²)
11-13/16" (300 mm)	1" (25 mm)	< 0.01" (< 0.25 mm)	< 0.01" (< 0.25 mm)	< 0.01" (< 0.25 mm)	< 0.01" (< 0.25 mm)	0.01" (0.26 mm)	0.01" (0.31 mm)	0.03" (0.64 mm)	6,477 (31,625)
11-13/16" (300 mm)	1-1/2" (38 mm)	< 0.01" (< 0.25 mm)	< 0.01" (< 0.25 mm)	< 0.01" (< 0.25 mm)	< 0.01" (< 0.25 mm)	< 0.01" (< 0.25 mm)	< 0.01" (< 0.25 mm)	0.02" (0.42 mm)	8,561 (41,800)
17-3/4" (450 mm)	1" (25 mm)	0.01" (0.3 mm)	0.01" (0.38 mm)	0.02" (0.62 mm)	0.04" (0.94 mm)	0.05" (1.22 mm)	0.07" (1.85 mm)	0.11" (2.75 mm)	4,252 (20,759)
17-3/4" (450 mm)	1-1/2" (38 mm)	0.01" (0.2 mm)	0.01" (0.25 mm)	0.02" (0.41 mm)	0.02" (0.62 mm)	0.03" (0.81 mm)	0.05" (1.22 mm)	0.07" (1.81 mm)	5,620 (27,439)
23-5/8" (600 mm)	1" (25 mm)	0.04" (0.98 mm)	0.05" (1.24 mm)	0.07" (1.85 mm)	0.11" (2.75 mm)	0.13" (3.35 mm)	0.20" (5.18 mm)	0.35" (8.86 mm)	2,548 (12,439)
23-5/8" (600 mm)	1-1/2" (38 mm)	0.03" (0.65 mm)	0.03" (0.81 mm)	0.05" (1.22 mm)	0.07" (1.81 mm)	0.09" (2.2 mm)	0.22" (5.64 mm)	0.56" (14.1 mm)	3,367 (16,441)
29-1/2" (750 mm)	1" (25 mm)	0.05" (1.28 mm)	0.12" (3.05 mm)	0.18" (4.57 mm)	0.27" (6.86 mm)	0.36" (9.15 mm)	—	—	1,628 (7,950)
29-1/2" (750 mm)	1-1/2" (38 mm)	0.02" (0.48 mm)	0.08" (2.01 mm)	0.12" (3.01 mm)	0.18" (4.51 mm)	—	—	—	2,152 (10,508)
35-7/16" (900 mm)	1" (25 mm)	0.10" (2.57 mm)	0.28" (7.13 mm)	0.38" (9.62 mm)	—	—	—	—	1,130 (5,518)
35-7/16" (900 mm)	1-1/2" (38 mm)	0.07" (1.69 mm)	0.14" (3.62 mm)	0.22" (5.61 mm)	0.33" (8.42 mm)	—	—	—	1,494 (7,293)
47-1/4" (1200 mm)	1" (25 mm)	0.28" (7.1 mm)	0.39" (9.9 mm)	0.49" (12.46 mm)	—	—	—	—	579 (2,827)
47-1/4" (1200 mm)	1-1/2" (38 mm)	0.18" (4.67 mm)	0.26" (6.51 mm)	0.37" (9.3 mm)	0.55" (13.95 mm)	—	—	—	880 (4,297)

Cells are deflection under static load at ambient temperature, as printed in Strongrate’s 2023 catalog (mm), with inches converted; “—” means no value is printed. Halve the loads for impact or dynamic conditions. Confirm the values for your span in the submittal before final design.

Notes

Deflections as printed in the factory catalog (2023), static loads at ambient temperature.
Catalog tables.

Pultruded tables are organized by type rather than depth. I-4015, I-5015 and I-6015 are 1-1/2" (38 mm) deep I-bar types; line loads in this table start at 202 lb/ft (300 kg/m). Uniform-load rows are on 1-1/2" I-bar grating, and the 1" (25 mm) types on 1" I-bar grating.

Concentrated line load deflection, Strongrate pultruded grating, I-series (catalog page 72)

Clear span	Type	202 lb/ft (300 kg/m)	302 lb/ft (450 kg/m)	504 lb/ft (750 kg/m)	1,008 lb/ft (1,500 kg/m)	2,016 lb/ft (3,000 kg/m)	3,998 lb/ft (5,950 kg/m)	Max load, lb/ft (kg/m)
17-3/4" (450 mm)	I-4015	—	0.01" (0.25 mm)	0.02" (0.51 mm)	0.03" (0.76 mm)	0.06" (1.52 mm)	0.11" (2.79 mm)	17,616 (26,215)
23-5/8" (600 mm)	I-4015	0.02" (0.51 mm)	0.02" (0.51 mm)	0.04" (1.02 mm)	0.07" (1.78 mm)	0.12" (3.05 mm)	0.23" (5.84 mm)	13,212 (19,661)
35-7/16" (900 mm)	I-4015	0.04" (1.02 mm)	0.05" (1.27 mm)	0.09" (2.29 mm)	0.17" (4.32 mm)	0.33" (8.38 mm)	0.66" (16.76 mm)	8,537 (12,705)
47-1/4" (1200 mm)	I-4015	0.08" (2.03 mm)	0.11" (2.79 mm)	0.18" (4.57 mm)	0.37" (9.4 mm)	0.75" (19.1 mm)	1.49" (37.85 mm)	6,106 (9,086)
17-3/4" (450 mm)	I-5015	—	0.01" (0.25 mm)	0.02" (0.51 mm)	0.04" (1.02 mm)	0.07" (1.78 mm)	0.13" (3.3 mm)	14,673 (21,836)
23-5/8" (600 mm)	I-5015	0.02" (0.51 mm)	0.02" (0.51 mm)	0.04" (1.02 mm)	0.07" (1.78 mm)	0.14" (3.56 mm)	0.27" (6.86 mm)	11,010 (16,385)
35-7/16" (900 mm)	I-5015	0.04" (1.02 mm)	0.06" (1.52 mm)	0.10" (2.54 mm)	0.20" (5.08 mm)	0.39" (9.91 mm)	0.79" (20.07 mm)	7,107 (10,576)
47-1/4" (1200 mm)	I-5015	0.09" (2.29 mm)	0.14" (3.56 mm)	0.23" (5.84 mm)	0.47" (11.94 mm)	0.92" (23.4 mm)	1.85" (46.99 mm)	5,085 (7,567)
17-3/4" (450 mm)	I-6015	—	0.01" (0.25 mm)	0.02" (0.51 mm)	0.03" (0.76 mm)	0.08" (2.03 mm)	0.15" (3.81 mm)	11,741 (17,472)
23-5/8" (600 mm)	I-6015	0.02" (0.51 mm)	0.03" (0.76 mm)	0.04" (1.02 mm)	0.09" (2.29 mm)	0.17" (4.32 mm)	0.33" (8.38 mm)	8,808 (13,108)
35-7/16" (900 mm)	I-6015	0.05" (1.27 mm)	0.08" (2.03 mm)	0.13" (3.3 mm)	0.24" (6.1 mm)	0.49" (12.5 mm)	0.99" (25.15 mm)	5,685 (8,460)
47-1/4" (1200 mm)	I-6015	0.11" (2.79 mm)	0.17" (4.32 mm)	0.28" (7.11 mm)	0.56" (14.22 mm)	1.12" (28.5 mm)	2.24" (56.9 mm)	4,063 (6,047)

Notes

Deflections as printed in the factory catalog (2023), static loads at ambient temperature.
Catalog tables.

How do you read fiberglass grating load tables?

US load tables run by clear span, the distance between supports, typically from 12" (305 mm) up to 48" (1219 mm) or 72" (1829 mm). For each span they give the deflection under uniform loads (U, in psf) and under concentrated line loads (C, in lb per foot of panel width, at mid-span). The ANSI/ACMA FGMC grating manual (2nd edition, 2019) sets the conventions most US specifications reference.

Terms used in fiberglass grating load tables and what each one tells you

Term	Unit, imperial (metric)	What it tells you
Clear span	in (mm)	Distance between the faces of the supports that carry the grating
Uniform load (U)	psf (kPa)	Load spread evenly over the panel, such as foot traffic or stored material
Concentrated line load (C)	lb per ft of panel width (kN/m)	Load applied across the full panel width at mid-span
Concentrated point load	lb (kN) over a stated contact area	Load on a small area, such as a wheel or equipment foot
Deflection	in (mm)	How far the panel bends at mid-span under the listed load
Ultimate capacity	psf or lb	Load at failure in test, from which a lower working value is derived
Recommended (safe) load	psf or lb	Ultimate capacity divided by the safety factor, which ranges from 2:1 to 5:1 between makers

Measure the clear span between the supports the grating will bear on.
Open the table for your exact product: depth, mesh or bar profile, and resin.
Choose the load case that matches your design load: uniform (U) for foot traffic, line load (C) or point load for wheels and equipment.
Read the deflection at your design load and compare it with the limit your engineer has set.
Confirm the design load is at or below the recommended load, not the ultimate load, and halve tabulated loads for impact.

Safety factors differ by maker, from 2:1 to 5:1 on ultimate capacity, so headline "safe" loads from different tables are not comparable: compare deflection at your span, and design only from the table for the exact product you buy.

Which deflection limit and design load should you check?

The project engineer sets both; OSHA 29 CFR 1910.22(b) requires each walking-working surface to support its maximum intended load. These are the values US guide specifications and load-table notes commonly use.

Design loads and deflection limits used for fiberglass grating in US guide specifications and load-table notes

Criterion	Value, imperial (metric)	Or span ratio
Deflection limit for pedestrian comfort	3/8" (9.5 mm)¹	L/120¹
Deflection limit for a firmer feel	1/4" (6.4 mm)¹	L/200¹
Typical pedestrian load	50–65 psf (2.4–3.1 kPa)²	—
Walkway design load, uniform (guide specifications)	60–100 psf (2.9–4.8 kPa)³	—
Walkway design load, concentrated (guide specification)	300 lb (1.3 kN)³	—
Stair tread design load, uniform	100 psf (4.8 kPa)	—
Stair tread design load, concentrated over 4 in² (2581 mm²)	300 lb (1.3 kN)	—
Stair capacity (OSHA 29 CFR 1910.25): 5 × the normal live load, and never less than	1,000 lb (4.4 kN)	—
Deflection of supporting members	—	L/180

L is the clear span. The project specification and the governing code take precedence.

Notes

1The project engineer sets the deflection criterion.
2The governing design load comes from the project specification and code.
3Use the project’s governing criteria.

L/120 means deflection may not exceed the clear span divided by 120. At a 36" (914 mm) span that is 0.3" (7.6 mm), which governs over a fixed 3/8" (9.5 mm) limit when the specification says "whichever is less".

How much weight can fiberglass grating hold?

It depends on depth, mesh or profile, span and the maker's test basis; at a 24" (610 mm) span, published US recommended uniform loads for 1-1/2" (38 mm) square-mesh molded grating run from about 780 psf (37.3 kPa) to 1,190 psf (57.0 kPa). Pultruded grating is stiffer along its bars and spans farther; see molded vs pultruded fiberglass grating.

Halve tabulated loads for impact or dynamic loads, and allow for creep under sustained load and for elevated temperatures. Vehicles need a wheel-load table, not a pedestrian table; see fiberglass trench covers and drain grates. The DNV type approval is a fire evaluation and does not rate load capacity.

Send your span, design load and deflection limit with a quote request, and the reply confirms the table that applies to your product. The price basis is on fiberglass grating price per square foot.

Frequently asked questions

What safety factor do Strongrate’s load tables use?

The catalog’s grating tables do not state one, so ask for it with your quote. Published US tables use 2:1 to 5:1 on ultimate capacity, so check the factor before comparing products.

Fiberglass grating technical resources
Index of fiberglass grating technical resources (load tables, sizes and weights, specifications, fire ratings, how-to guides, comparisons) and the standards they cite.
Fiberglass grating sizes, weight and open area
Strongrate’s catalog size tables for molded and pultruded fiberglass grating (depth, weight, open area, panel sizes), common US panel sizes, and how to work out panel weight.
Fiberglass grating specifications
An editable three-part CSI MasterFormat 06 74 13 guide specification for molded and pultruded fiberglass grating, with specifier’s notes, origin and warranty options, Strongrate catalog material data and a compliance table.
Molded vs pultruded grating
How molded and pultruded fiberglass grating differ in manufacture, glass content, stiffness, weight, open area and cost, with a decision table by application.
How to install fiberglass grating
How to install fiberglass grating: support bearing, span direction, clip layout and counts per panel, cut-outs, guardrails, inspection and expansion gaps.
Fiberglass grating clips
Hold-down clips for molded and pultruded fiberglass grating: the STRONGFIX types in Strongrate’s catalog, common US clip types, the Type 316 stainless and 4 ft spacing rules in US guide specifications, and how to order clips with grating.

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Sources

Strongrate product catalog “Your Best FRP Solution” (image PDF, Sep 2023), supplied by the site owner (accessed Oct 17, 2026)
ACMA, release of the 2nd edition national standard fiberglass grating manual (accessed Oct 15, 2026)
Fibergrate industrial pultruded load tables; Strongwell pultruded load tables; Bedford I 15-60; McNichols LT-M-MSS150 (accessed Oct 15, 2026)
Fibergrate molded grating guide specification (Section 06610) (accessed Oct 15, 2026)
Strongwell Section 06 74 13 pultruded spec (revised Nov 2024) (accessed Oct 15, 2026)
OSHA 29 CFR 1910.22, Walking-working surfaces: general requirements (accessed Oct 15, 2026)
OSHA 29 CFR 1910.25, Stairways (accessed Oct 15, 2026)