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Product specification

1-1/2" I-Bar Pultruded Fiberglass Grating

Updated

Strongrate's catalog lists three 1-1/2" (38 mm) I-bar pultruded grating types: I-4015, I-5015 and I-6015, at 40%, 50% and 60% open area and 3.3–4.5 lb/ft² (16.1–22.0 kg/m²). I-6015 is DNV-listed model I 6015, which in isophthalic resin has an ASTM E84-19a flame spread index of 20 and a smoke-developed index of 400.

Specifications: 1-1/2" (38 mm) I-bar pultruded grating

Profile
Pultruded I-bars joined by cross bars bonded with epoxy
Bar depth
1-1/2" (38 mm)Values as printed in the factory catalog (2023); confirmed in your quote and submittal drawings.
Catalog types
I-4015, I-5015, I-6015Values as printed in the factory catalog (2023); confirmed in your quote and submittal drawings.
Open area
40%, 50% and 60%Values as printed in the factory catalog (2023); confirmed in your quote and submittal drawings.
Weight
3.3–4.5 lb/ft² (16.1–22.0 kg/m²)Values as printed in the factory catalog (2023); confirmed in your quote and submittal drawings.
Cross-bar centers
6" (152 mm)Values as printed in the factory catalog (2023); confirmed in your quote and submittal drawings.
Glass content
60–65%
Resins
Fire-retardant vinyl ester (VEFR), isophthalic polyester (IFR) or food-grade isophthalic (FG)Maximum service temperatures as printed in the catalog’s resin table; its chemical-resistance chart prints lower maximums.
Surfaces
Corrugated (slotted), gritted or smooth top; solid cover with checker or grit finish
Maximum panel size
5 ft × 20 ft (1524 × 6100 mm)Values as printed in the factory catalog (2023); confirmed in your quote and submittal drawings.
Standard panel sizes
On request
Bar dimensions and clear opening
On request
Colors
On request
Tolerances
On request
Pultruded I-bar fiberglass grating, sectionSection through four parallel I-shaped load bars joined by a cross rod, showing bar spacing center to center, the depth and the openings between bars.Section across the load barsBar spacingcenter to centerI-bar (load bar)DepthOpeningCross rodPultruded I-bar fiberglass grating, plan viewPlan strip showing parallel load bars held at a fixed spacing by cross rods that run across them.PlanLoad barsCross rods
1-1/2" I-bar pultruded grating: I-shaped bearing bars joined by a cross bar, in section and planSchematic — not to scale

Which 1-1/2" I-bar types does Strongrate list?

The three types differ in bearing-bar spacing: closer bars give smaller openings and more weight. I-6015, the most open, is the type DNV lists as I 6015. Panels run up to 5 ft × 20 ft (1524 × 6100 mm), with the bearing bars along the panel length.

Strongrate 1-1/2" (38 mm) I-bar pultruded grating types: catalog data
TypeBar shapeDepthBearing-bar centersCross-bar centersOpen areaWeight
I-40151I-bar1-1/2" (38 mm)11.00" (25.4 mm)16" (152 mm)140%14.5 lb/ft² (22.0 kg/m²)1
I-50151I-bar1-1/2" (38 mm)11.20" (30.5 mm)16" (152 mm)150%13.9 lb/ft² (19.1 kg/m²)1
I-60151I-bar1-1/2" (38 mm)11.46" (37.1 mm)16" (152 mm)160%13.3 lb/ft² (16.1 kg/m²)1
As printed in Strongrate’s 2023 product catalog; confirmed in your quote and submittal drawings. Weights and open areas are from the catalog’s summary table; some of its detail cards print different values.

Notes

  1. 1Values as printed in the factory catalog (2023).

The catalog also lists I-40125, I-50125 and I-60125 at 1-3/16" (30 mm) with the same open areas, without a load table. The shallowest types are on 1" I-bar grating.

How much load can 1.5 inch pultruded fiberglass grating carry?

Find your clear span, then read deflection under your design load. Typical pedestrian loads are 50–65 psf (2.4–3.1 kPa), and common deflection limits are 3/8" (9.5 mm) or L/120 for comfort and 1/4" (6.4 mm) or L/200 for a firmer feel. Halve tabulated loads for impact or dynamic conditions.

Concentrated line load deflection, Strongrate 1-1/2" (38 mm) I-bar types (catalog page 72)
Clear spanType202 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-40150.02" (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-40150.04" (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-40150.08" (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-50150.02" (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-50150.04" (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-50150.09" (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-60150.02" (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-60150.05" (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-60150.11" (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)
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.
Uniform load deflection, Strongrate 1-1/2" (38 mm) I-bar types (catalog page 73)
Clear spanType205 psf (1,000 kg/m²)389 psf (1,900 kg/m²)799 psf (3,900 kg/m²)1,434 psf (7,000 kg/m²)1,946 psf (9,500 kg/m²)3,994 psf (19,500 kg/m²)Max load, psf (kg/m²)
23-5/8" (600 mm)I-40150.01" (0.25 mm)0.01" (0.25 mm)0.03" (0.76 mm)0.05" (1.27 mm)0.06" (1.52 mm)0.13" (3.3 mm)23,481 (114,645)
31-1/2" (800 mm)I-40150.02" (0.51 mm)0.03" (0.76 mm)0.06" (1.52 mm)0.11" (2.79 mm)0.15" (3.81 mm)0.30" (7.62 mm)13,212 (64,506)
39-3/8" (1000 mm)I-40150.06" (1.52 mm)0.11" (2.79 mm)0.21" (5.33 mm)0.40" (10.2 mm)0.53" (13.46 mm)—5,685 (27,757)
47-1/4" (1200 mm)I-4015—0.34" (8.64 mm)————3,053 (14,905)
23-5/8" (600 mm)I-50150.01" (0.25 mm)0.02" (0.51 mm)0.03" (0.76 mm)0.05" (1.27 mm)0.07" (1.778 mm)0.14" (3.56 mm)19,568 (95,537)
31-1/2" (800 mm)I-50150.02" (0.51 mm)0.03" (0.76 mm)0.06" (1.52 mm)0.12" (3.05 mm)0.16" (4.06 mm)0.32" (8.13 mm)11,010 (53,755)
39-3/8" (1000 mm)I-50150.07" (1.78 mm)0.13" (3.3 mm)0.24" (6.1 mm)0.46" (11.7 mm)0.61" (15.49 mm)—4,744 (23,164)
47-1/4" (1200 mm)I-50150.22" (5.59 mm)0.42" (10.63 mm)————2,544 (12,422)
17-3/4" (450 mm)I-60150.01" (0.25 mm)0.01" (0.25 mm)0.03" (0.76 mm)0.05" (1.27 mm)0.07" (1.78 mm)0.14" (3.56 mm)15,654 (76,430)
23-5/8" (600 mm)I-60150.02" (0.51 mm)0.04" (1.02 mm)0.07" (1.789 mm)0.13" (3.3 mm)0.18" (4.57 mm)0.35" (8.89 mm)8,808 (43,004)
35-7/16" (900 mm)I-60150.09" (2.29 mm)0.16" (4.06 mm)0.31" (7.87 mm)0.58" (14.7 mm)——3,803 (18,570)
47-1/4" (1200 mm)I-60150.26" (6.6 mm)0.51" (12.95 mm)————2,032 (9,920)
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.

If 1-1/2" misses your load or deflection limit, step up to 2" T-bar grating. Pultruded grating is marketed as about twice as stiff as molded, so also compare 1-1/2" molded grating at the same span. How to read the columns: fiberglass grating load tables.

What does the DNV certificate say about I-bar model I 6015?

DNV-listed pultruded I-bar model I 6015: what the certificate states
ItemModel I 6015
CertificateDNV Type Approval TAF0000191 Rev. 11
Valid untilFeb 10, 2027
ResinIsophthalic polyester2
ASTM E84-19a flame spread index (FSI)203
ASTM E84-19a smoke-developed index (SDI)4003
Structural fire integrityL0 per ASTM F3059-154
As listed on the certificate, which covers fire performance only, not load capacity.

Notes

  1. 1The approval covers fire-technical properties of the six listed models only, not structural strength, and acceptance is case by case.
  2. 2Bar depth and open area are not stated on the certificate.
  3. 3Result as listed on DNV certificate TAF0000191 Rev. 1 (ASTM E84-19a); applies to this model only.
  4. 4As stated on the certificate; acceptance for a given location is case by case.

FSI 20 is within the 25 that US specifications call Class 1 or Class A, and SDI 400 is within the 450 building-code limit; check any tighter smoke limit in your specification. The results apply to I 6015 in isophthalic resin. More on ASTM E84 Class 1 fire rating.

Which resins and surfaces are offered at 1-1/2"?

Fire-retardant vinyl ester (VEFR, up to 230°F (110°C)), isophthalic polyester (IFR, up to 176°F (80°C)) or food-grade isophthalic polyester (FG). Tops are corrugated, gritted or smooth, with solid covers in checker or grit finish. Resins are compared on pultruded fiberglass grating.

How do you order 1-1/2" I-bar grating?

Made in Nantong, China, and shipped from China. Full containers and project quantities are quoted factory-direct; orders under about 500 sq ft, or needed in under 3 weeks, are referred to US stock. See the fiberglass grating price per square foot basis or request a quote.

Frequently asked questions

Is Strongrate model I 6015 a 1-1/2" deep I-bar?

Yes, according to Strongrate's catalog, which lists I-6015 at 1-1/2" (38 mm) deep and 60% open. The DNV certificate itself states neither depth nor open area.

Can isophthalic I-bar grating be used outdoors?

FRP exposed to weather should contain an ultraviolet inhibitor. Strongrate’s catalog states that its colors stay stable for more than 12 months in sunlight and gives a designed lifespan of more than 20 years; these are catalog statements, not a warranty.

When should I step up from 1" to 1-1/2" I-bar grating?

When the 1" load table at your clear span misses your design load or deflection limit. Strongrate’s catalog prints line-load tables for both depths at the same spans, so compare them side by side.

Request a quote

Send the type (I-4015, I-5015 or I-6015), clear span, design load, deflection limit, resin, panel size, quantity and ZIP code. Quotes within 1 business day (US Central time).

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Sources
  1. Strongrate product catalog “Your Best FRP Solution” (image PDF, Sep 2023), supplied by the site owner (accessed Oct 17, 2026)
  2. DNV Type Approval Certificate TAF0000191 Rev. 1, including ASTM E84-19a results (PDF hosted on Strongrate’s ShipServ supplier profile) (accessed Oct 15, 2026)
  3. Fibergrate industrial pultruded load tables (PDF) (accessed Oct 15, 2026)
  4. Fiberglass-AFI, Fire-retardant FRP and the FRP fire code (summary of the IBC) (accessed Oct 15, 2026)