Leading FRP Manufacturer Achieves ASTM F3059-18 Certification for Phenolic Grating

Fibergrate Composite Structures Inc. is pleased to announce the recent successful certification of its Firewalk™ Phenolic Pultruded Grating to the full requirements of ASTM F3059-18 at the L2 standard. The certification covers all standard bar configurations of the 1-1/2” (38mm) thick phenolic grating.

The ASTM F3059-18 standard was developed to replace the PFM 2-98 standard established in 1998. The specification is “intended to provide testing and performance requirements for FRP gratings used in marine construction and shipbuilding as an equivalency to the specification for steel gratings rated for a maximum load of 94 psf (4.5 kN/m²)”. 

Functionally, the standard combines 10 different test protocols under one certification, managed by one certification authority, thereby ensuring the owner is receiving the same grating tested to the standard. One of the test protocols (Section #17) defines one of three levels of structural fire integrity which classifies FRP grating for use in different locations on a vessel. The most current standard is F3059-18 and is currently under review for the next revision cycle. 

The standard consists of 10 test protocols. Some are related to structural requirements and some for durability requirements. The last two are related to flammability and structural fire integrity. The results for the last two provide a rating for structural fire integrity only. The certificate for Fire Integrity should not be confused for a certificate for the full standard.

The first protocol is in Section 8 of the standard and is currently defined as “Deflection Limits”. To pass this test, a grating must deflect less than 0.25” (0.6 cm) when tested at 150 psf (7.2 kn/m²) at the qualified span (44”).

Section 9 is currently defined as “Assembled Grating Ultimate Failure” but is more simply a measure of flexural strength. The tested panel must have a minimum flexural strength of 50,000 psi (344,738 kPa) when tested at the qualified span

Section 10 is currently defined as “Wheel Loading” and tests both strength and durability of the grating. A 2” (5 cm) wide hard rubber wheel, loaded to 1000 lbs (454 kg), is passed back and forth on the grating over a 24” (61 cm) long pass 1000 times at a minimum rate of 10 passes per minute. The pass-fail criteria are no visual cracks in the grating bars and the surface should not be worn down more than 0.03” (0.8mm). The panel is tested at the qualified span.

Section 11 is called “Assembled Panel Impact Resistance”. A load with a steel impact surface no more than 6” (15 cm) wide and 20” (51 cm) long is allowed to freefall from a minimum of 36” (91 cm) onto a piece of grating no more than 12-7/8” (352mm) wide so that the impact generates an impact load of 12000 in-lbs (68,250 mm-N). The pass-fail criteria is retention of flexural strength of at least 90% of a control panel. Test is performed at the qualified span of 44”.

Section 12 is “Skid Resistance” and is measured per ASTM test method D2047. Coefficient of friction must be 0.75 or greater

Section 13 is “Durability” and is measured per ASTM test method D4060. One sample is tested as a control and the second sample is tested to ASTM practice D4329 Cycle A for a minimum of 720 hours. Both samples require at least 1200 cycles before wearing through the grit.

Section 14 is “UV resistance”. Grating samples are subject to accelerated weathering in accordance with ASTM practice D4329. No visible evidence of damage should be visible on the sample in order to pass this test. 

Section 15 is “Saltwater Spray Test”. A sample of grating is exposed to saltwater spray per ASTM practice B117 for 7 days. After 7 days the grating is tested for flexural strength per Section 9 and it must pass the same criteria. 

Section 16 covers “Surface Flammability”. Four pieces of grating are tested per ASTM test method E84. The samples are tested upside down and right side up, UV coated/gritted and uncoated. Acceptance criteria is flame spread index <= 20 and smoke developed index <=450.

Section 17 is “Structural Fire Integrity”. This is the most complicated of the sections and will result in a fail, Level 1 (L1), Level 2 (L2) or Level 3 (L3) result. No fire integrity testing is done for Level 0 (L0) grating. A minimum of two samples is required for the Level 2 and 3 testing. Four samples are required for Level 1 testing. Samples are tested without any coatings and at the qualified span of 44”.

For L1, L2 and L3 tests, two samples are placed in an oven. A 88 lb (392 N) load is placed on the middle of one of the samples. The grating is exposed to a temperature conforming to the temperature curve defined by ASTM test method E119 which reaches a maximum temperature of 1701 ^oF (927^oC). A L3 rating is reached if the preloaded sample does not deflect more than L/10 within the first 18 minutes of exposure and the unloaded sample does not collapse during the test. 

An L2 rating is reached if the grating passes the L3 requirements and the grating is able to carry a post load test of 94 psf (4.5 kN/m²) for 15 minutes. An L1 rating is reached if the grating passes the L2 and L3 requirements and the two remaining pieces pass the impact testing requirements of ASTM Test Method E695, where a bag of lead shot weighing 88 lbs (40 kg) is dropped on the midspan of a piece of grating from a minimum height of 78-3/4” (200 cm).

The results from Sections 16 and 17 can sometimes be combined into a partial F3059 certification for fire integrity only. While this partial certification is a worthy achievement, it does not reflect the full certification requirements for non-fire related structural performance, weathering or slip resistance and durability. 

The F3059 standard also provides helpful information related to FRP composite grating in general, installation, attachments, penetrations and inspection points. Those who are interested in the standard can order a copy here.

Having access to a manufacturer of phenolic pultruded grating that meets the most stringent, up-to-date standard provides a way for those specifying and using phenolic grating in their marine applications to fully meet their project requirements. Fibergrate Composite Structures remains committed to developing and supplying the highest quality FRP materials on the market. 

For any other questions, contact Bill Budgell, VP of Product and Corporate Development at bbudgell@fibergrate.com.