An excavation, disturbed walkway or damaged road poses a danger to workers, pedestrians and passing vehicles. Steel road plates, also known as street plates or trench plates, are an effective way to temporarily cover holes. But not all road plates are created equal, and using the wrong type, or size, of road plate or installing it incorrectly can lead to potentially disastrous outcomes.

Here are six common mistakes people make when choosing and using road plates and tips for avoiding them.

1. Using the wrong grade of steel

l steel plates are the same. According to the World Steel Association, there are more than 3,500 grades of steel. If you go to a local steel supplier for road plates, you risk getting plates made from whatever steel they have available.

A36 steel is the industry standard for road plates and a popular choice for many construction applications. Made primarily of low-carbon steel, it’s strong and durable and more pliable than higher-grade steel, which is prone to fracture and crack on uneven road surfaces. It’s economical and widely available, so professional engineers frequently specify A36 steel plates in project plans.

If you rent road plates, you will likely get plates made from A36 steel. Equipment rental companies such as United Rentals offer A36 steel plates in sizes ranging from 4-by-4-foot plates to 8-by-20-foot plates.

2. Miscalculating the plate size and thickness needed

It’s easy to make a mistake when sizing a road plate. A plate can’t be used on spans greater than those indicated in the manufacturer’s tabulated data. A 1-inch A36 steel plate is rated to a span of 4.5 feet. If you need to cover a larger span, you’ll need a thicker plate. A span is defined as edge of asphalt to edge of asphalt or edge of trench to edge of trench plus 6 inches on each side.

The load traveling over the plate is another factor in plate selection. A 1-inch A36 steel plate is rated for HS-20-44 loading—that is, it can support vehicles with a per axle load of up to 32,000 pounds.

Insufficient overlap is another common size mistake, one that can lead to accidents and fines. If vehicle speeds are less than 45 mph, a minimum overlap of 12 inches on each side is required with a 1-inch steel plate. At higher speeds, a minimum of 24 inches of overlap on each side is required.

One way to cover more span is to slow down traffic in the work zone. Allowable span increases by 20% with speeds that are less than 10 mph.

3. Not properly securing plates

Any movement of road plates can create an uneven surface or expose a hole. In some cases, it’s necessary to secure road plates to the ground so they don’t rock, shift or slide. The vehicle speed and how the plate is positioned relative to the excavation can affect whether to anchor. Consult the tabulated data.

There are several ways to secure plates. Commonly used anchoring systems include railroad spikes, drilled-in bolts, asphalt anchoring and recessing the plate into the road surface. Tapered ramps can be installed on both sides, as needed, to smooth the transition between the plate edge and the road.

Mark road plates with cones and signs to make drivers and pedestrians aware of them.

4. Failing to designate a competent person to ensure proper usage

A competent person should be designated to make sure tabulated data is interpreted properly and steel road plates are chosen and used per tab data requirements. It is this person’s responsibility to keep the worksite conditions safe.

The designated person must have the requisite knowledge and experience to do the job. OSHA defines a competent person as "one who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them."

5. Not requesting non-skid plates

Street plates are notoriously slippery when wet. Many municipalities and project owners require that plates have a skid-resistant surface with a coefficient of friction not less than 0.35 percent.

If you’re renting plates, they may come with a non-skid coating -- but don’t forget to ask for it if you’re renting or purchasing plates.

6. Skipping plate inspections

The competent person should see to it that plates are routinely inspected throughout the project. A worn or defective picking key (a lifting ring or screw in the center of the plate) could cause a plate to drop during movement.

When renting steel road plates from United Rentals, you can be assured that they are inspected prior to delivery.

On construction sites and road projects, steel road plates are crucial in allowing pedestrian, equipment and vehicle traffic flow over an excavation or other hole. By avoiding these common plate mistakes, you can reduce the risk of accidents and maintain a safer worksite.

Visit our online marketplace to browse our selection of road plates.