Jensen MetalTech Guidelines
Jensen MetalTech follows standards set by the American Society for Testing and Materials (ASTM) in product designs. Our engineers share a history of collaboration with ASTM for introducing new standards and updating current ones. We periodically publish guidelines about our products in relation to these standards.
ASTM issues Standard Specification C1802 to promote the safe and proper selection, design, manufacture, identification, and installation of fabricated steel and aluminum access hatches used for vertical access to underground utilities. Jensen MetalTech adheres to this standard for determining the right load levels of hatches for your project to ensure the highest level of safety and product longevity.
For a complete overview of C1802, visit www.astm.org.
Determining Correct Load Levels for Metal Access Hatches
Utility, water, and wastewater engineers and contractors regularly specify metal access hatches for their infrastructure projects. There are several misunderstandings related to traffic ratings and the terminology surrounding the topic. Many people believe if a hatch is rated as “traffic” it is automatically considered ready to put into a roadway with moving vehicles traveling over the designated area. In practice, the term “traffic” covers everything from lawn equipment driving over a cover in a landscaping area to a passenger vehicle in a parking lot to a semitrailer truck on an interstate. It is important to be able to ask the right questions to make sure that the traffic rating requested will work for the specific application.
Note: There are potentially negative consequences to selecting under designed covers. Conversely, overdesigned covers may not realize the economic benefits for a business when selecting proper covers for proper applications.
Understanding AASHTO Highway Design Loading
What are H20 and HS20 loading?
H20 is the most used term for traffic load ratings across industries. The American Association of State Highway and Transportation Officials (AASHTO) designates the load rating for a vehicle with the letter “H” for “highway,” followed by the number of tons the vehicle weighs.
H20 is defined by AASHTO as a fully loaded 20 ton truck, bearing a 32,000 lbs. maximum axle weight or 16,000 lbs. wheel weight over a 10”x 20” footprint. H20 assumes a single axle is the only load on top of the structure being designed.
Another common designation used is HS20. The “S” stands for “semitrailer” and indicates a design truck with an additional axle spaced a minimum of 14’ apart. If the structure is large enough that more than one axle can sit on the structure at the same time, the structure must be designed for an HS20 wheel load.
What is HL93?
Highway designs using AASHTO Load and Resistance Factor Design (LRFD) replace the HS20 truck rating with a HL93 design. “HL” means “highway load,” and the standard was proposed in 1993. As it applies to underground structures, the HL93 designation consists of a design truck and design tandem. The HL93 design truck is identical to the HS20 configuration. The design tandem consists of twin axles spaced at 4’ apart, with the weight of each axle being 25,000 lbs.
What are ASTM C1802 Load Levels?
While AASHTO HS20 and HL93 loading addresses design considerations for highway structures, it does not specifically address design considerations of metal structures such as impact and fatigue factors. Engineers commonly specify a H20 traffic loading for utility access hatches, yet manufacturers typically need application details before supplying the appropriate product. Products designated H20 Incidental and H20 for off street use are not designed consistently from manufacturer to manufacturer. By specifying the appropriate ASTM C1802 load level, a specifier can be assured getting the right hatch for the right application. For example, Load Levels 4-7 are all considered H20 traffic rated, but each has intended areas of use designations.
Load Level 1 - Light Pedestrian
- Area of Use: Restricted to walkways and other areas fully inaccessible to all vehicle traffic.
Uniform / wheel load: 150 psf or 300 lbs. on 5.5"x5.5" footprint controlling case Load Level 2 - Pedestrian
- Area of Use: Restricted to pedestrian and light maintenance vehicle use. Inaccessible to all other vehicle traffic.
Uniform / wheel load: 300 PSF OR 600 lbs. on 5.5" x 5.5" footprint Load Level 3 - Light Vehicular Traffic
- Area of Use: Restricted to parking spaces accessible only to passenger vehicles and protected areas in close proximity of roadways.
Wheel load: 8,000# on 10"x 10" footprint Load Level 4 - Occasional Truck Traffic
- Area of Use: Restricted to parking spaces and areas in close proximity of roadways
Wheel load: 16,000# on 10"x20" footprint Load Level 5 - Off Street Truck Traffic
- Area of Use: Restricted to unrestricted parking lanes and alleyways where traffic is limited to 15 miles per hour.
Wheel load: 16,000# on 10" x 20" footprint Load Level 6 - Two Lane Vehicular/Truck Traffic
- Area of Use: Restricted to two lane streets with a maximum posted speed limit of 35 miles per hour.
Wheel load: 16,000# on 10" x 20" footprint Load Level 7 - Full Traffic
- Area of Use: For use in multi-lane roadways with a maximum posted speed limit of 70 miles per hour.
Wheel load: 16,000# on 10" x 20" footprint Load Level 8 - Occasional Aircraft
- Area of Use: For use in unpaved runway safety zones only.
Wheel load: Determined by airport design aircraft. Load Level 9 - Aircraft Loads
- Area of Use: For use in taxiways and aprons. Not for use in runways.
Wheel load: Determined by airport design aircraft. Load Level 10 - Special Equipment Loads
- Area of Use: Such as mining equipment, port equipment, cranes, and earth moving equipment.
Wheel load: Determined by customer design criteria.
Jensen MetalTech
Jensen MetalTech, a division of Jensen Precast, designs, engineers, and manufactures steel and aluminum access hatches, doors, covers, and grates for utility applications. We provide our customers with industry leading engineering designs and load testing to insure maximum service life and minimize maintenance. Whether your next projects calls for a standard size or specified design or requirement, you can count on Jensen MetalTech to provide the knowledge.
Utility Products
- Electric Distribution and Transmission Pull Boxes, Manholes, Trenches, and Vault Covers
- Telecom and Fiber Optic Pull Boxes, Manholes, and Vault Covers
- Water Meter Vault Access Covers
- Pressure Reducing Station Access Hatches
- Backflow Preventer Vault Covers
- Fire Serv ice Vault Access Hatches
- Natural Gas Distribution Vault Hatch Covers
- Steam Trench Covers
Inventory, Customization and Delivery
- Many standard designs in stock for immediate delivery
- Custom hatch cover design and manufacturing
- In-house engineering calculations and/or proof load testing for load requirements
- Manufactured in steel or aluminum to accommodate a wide variety of load requirements from pedestrian to airport ratings
- All of our products can be shipped anywhere in the United States
Special Design Features
- Unique latch and hinge designs to provide safety and functionality
- Easily serviced assemblies make installation and repairs simple
- Optional delivery with companion products (vaults, pull boxes, etc.) for reduced installation costs
Additional Options
- TraxPlate proprietary slip-resistant safety floor plating for applications requiring slip and fall protection
- Spring assist doors for easier opening
- Variety of locking and security features
- Marking and identification