FRP vs Aluminum Grating for Walkways and Platforms

In short: FRP and aluminum grating are both light and both resist rust, so they are often compared for walkways and platforms. Aluminum is stiffer and does not burn, while FRP does not conduct electricity, resists a wider range of chemicals and is not affected by galvanic corrosion. Aluminum density is about 2.7 g/cm³; FRP is typically around 1.7 to 2.0 g/cm³. In chemical plants, wastewater sites, coastal areas and electrical areas, FRP is often the better fit. Where stiffness over long spans or non-combustibility matters most, aluminum may be preferred. FIBROVX makes FRP grating to order in the size, resin and color your project needs.

Side-by-side comparison

More properties compared

In North America, aluminum bar grating is described in the NAAMM Metal Bar Grating Manual (ANSI/NAAMM MBG 531). It allows bearing bars in alloys 6005A-T61, 6061-T6, 6105-T5 and 6063-T6, and the NAAMM engineering manual (MBG 534) uses a modulus of 69 GPa (10,000,000 psi) for all of them. The same manual uses a deflection of 0.25 in (6.4 mm) as the limit recommended for pedestrian comfort, a figure also common in FRP grating load tables.

Weight and handling

Both are much lighter than steel. FRP is usually lighter than aluminum for the same panel, which helps with manual handling and freight. Compare actual panel weights from data sheets, because depth and mesh vary.

Stiffness and span

Aluminum is stiffer than FRP. On long spans, FRP may need a deeper section or closer supports to meet the same deflection limit. Check both options with their own load tables at your span. See how to read FRP grating load tables.

Worked example: deflection on the same span

Suppose an FRP grating and an aluminum grating had the same shape and the same span and load. Deflection is inversely proportional to the modulus, so the FRP would deflect more:

In practice the two gratings never have the same shape, so this is only a guide to the direction of the difference. It shows why an FRP grating is often a size deeper than the aluminum grating it replaces, or sits on closer supports. The real answer comes from each product's load table at your span and deflection limit.

Corrosion

Aluminum resists normal weather well, but strong alkalis (such as caustic soda or wet concrete) and some acids attack it, and contact with steel or copper in wet conditions can cause galvanic corrosion. FRP has no galvanic issue and, with a resin selected for the chemical, resists many aggressive environments. See the FRP chemical resistance guide.

Electrical safety

FRP is non-conductive, which is why it is used near electrical equipment, in substations and in areas with stray current. Aluminum conducts electricity and must be bonded and grounded like other metal structures.

Fire

Aluminum does not burn. FRP is combustible, but fire-retardant resins can achieve low flame spread ratings in tests such as ASTM E84. Check the project's fire requirements. See fire performance of FRP grating.

Slip resistance and safety

Both materials can be made slip-resistant. FRP grating is offered with a molded concave (meniscus) top or a bonded grit surface, and aluminum grating with serrated bars. Wet, oily or icy areas need particular attention. ANSI A1264.2 is the US standard for the provision of slip resistance on walking-working surfaces, and OSHA 29 CFR 1910.22 requires walking-working surfaces to be kept free of hazards such as slippery conditions. See FRP grating surface options.

Lifecycle cost

Purchase price is only one part of the cost. Compare the two materials line by line:

In a mild, dry location, the two may end up close. In a chemical plant, wastewater site or near the sea, FRP's lower maintenance often decides it.

When to choose each

• Choose FRP for chemical plants, wastewater, coastal and marine areas, electrical zones and sites where alkalis are present.
• Choose aluminum when long spans need high stiffness, a non-combustible material is required, or the environment is dry and mild.

Installation differences

• Fixing. FRP panels are held with FRP or stainless steel hold-down clips. Aluminum grating uses clips, saddle clips or welding.
• Cutting. FRP is cut with carbide or diamond blades, and every cut edge is sealed with resin. Aluminum is cut with ordinary metal tools, and cut ends are usually banded.
• Dust and protection. Cutting FRP makes glass dust, so use dust extraction, masks and gloves.
• Supports. Aluminum on steel supports needs isolation in wet areas to avoid galvanic corrosion. FRP needs none.
• Tolerances. Both should be cut to a layout drawing before shipping, so less cutting is needed on site.

Specifying a replacement

If you are replacing aluminum grating with FRP, give the supplier:

• the existing panel sizes, depth and bar spacing, or a drawing;
• the clear span and support layout;
• the load and the deflection limit;
• the chemicals, temperature and UV exposure;
• any fire requirement, since FRP is combustible;
• how the panels are fixed today.

A like-for-like panel size makes the swap easy. The depth may change, so check the seat or frame height at the same time.

Decision guide by environment

Customization

FIBROVX makes FRP molded grating and other grating and access products to order: panel size, depth, mesh, resin, color and surface. Send your layout and service conditions for a recommendation.

Common mistakes

• Comparing price per square meter only. Include life, maintenance and installation.
• Using the aluminum span for FRP.
• Ignoring galvanic contact between aluminum and steel supports.
• Forgetting grounding for aluminum near electrical equipment.
• Placing aluminum against wet concrete without protection.
• Leaving FRP cut edges unsealed.

Key terms

• Modulus of elasticity: A measure of stiffness.
• Galvanic corrosion: Corrosion when two different metals touch in an electrolyte.
• Non-conductive: Does not carry electric current.

Watch: FRP vs Aluminum Grating for Walkways and Platforms in 27 Seconds

FAQ

Is FRP lighter than aluminum?

Usually yes, because FRP density is lower. Compare actual panel weights.

Which is stronger?

Both can carry walkway loads. Aluminum is stiffer; FRP may need a deeper section for the same span.

Does aluminum grating corrode?

It resists weather but can be attacked by strong alkalis, some acids and galvanic contact.

Which is better near electrical equipment?

FRP, because it is non-conductive.

Why is FRP grating often deeper than aluminum?

Because FRP is less stiff. To meet the same deflection at the same span, FRP often needs a deeper section or closer supports.

Can aluminum grating touch concrete?

Wet concrete and mortar are alkaline and can attack aluminum, so it is usually protected or isolated. FRP with a suitable resin is not affected.

Can FIBROVX replace existing aluminum grating?

Yes. Send the panel sizes, spans and loads of the existing grating. We will propose an FRP depth and mesh that meets the same load and deflection, cut to the same panel sizes.

Related guides

• FRP Grating Guide
• Molded vs Pultruded FRP Grating
• FRP Grating Thickness Selection
• FRP Grating Surface Options
• FRP Profiles vs Steel and Aluminum Sections
• Industries we serve

Sources

• The Aluminum Association, Aluminum alloys and properties: https://www.aluminum.org/
• ASM International / MatWeb, Aluminum 6061-T6 properties: https://www.matweb.com/search/DataSheet.aspx?MatGUID=b8d536e0b9b54bd7b69e4124d8f1d20a
• ASTM E84, Surface burning characteristics of building materials: https://www.astm.org/e0084-23.html
• NAAMM, Metal Bar Grating Manual (ANSI/NAAMM MBG 531-24): https://naamm.org/publications/metal-bar-grating-manual/
• ANSI/ASSP A1264.2, Provision of Slip Resistance on Walking/Working Surfaces: https://www.assp.org/standards/standards-topics/walking-working-surfaces-a1264
• OSHA 29 CFR 1910.22, Walking-working surfaces, general requirements: https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.22