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- AASHTO M306
- Light Duty or “Non-Traffic”– No roadway traffic. Pedestrian or hand truck traffic only.
- H-15 or “Medium duty”– Light duty traffic rating. 12,000 lb. wheel load or 75% of H20.
- H-20 or “Traffic-Rated”– Heavy duty traffic rating. Known as H-20, HS-20, heavy duty (HD) Designed for a 16,000 lb. wheel load (32,000 lb. dual spaced wheel load)
- Extra HD or “Airport-Rated”– Meets the design loading associated with the FAA wheel loading. Castings can accept loading from 200,000 lbs. and up and may include an additional safety factor beyond FAA design loading where noted and required.
Bass & Hays® does not recommend using standard meter boxes and covers for traffic use, even if they can “technically” hold up to traffic capacities under testing. We never have. We only recommend that standard meter boxes and covers be used in grassy or “foot traffic” areas in between the sidewalk and street, or in other foot traffic areas. Even our “light duty” traffic boxes that may technically pass H-20 traffic proof load tests are only recommended for use in light-duty traffic areas such as alley ways, parking lots, or drive ways, not for heavy duty H-20 traffic such as streets, and especially not highways.
For any type of cover to be used in a live traffic situation, many things must be taken into account. While it is important that proof load capacity be tested to recognized industry standards, it is also important to consider the deliberate load factors, live load factors, ultimate load factors, H-20 design requirements, and factors such as traffic speeds, rocking, rattling, vibrations, and noise. Specifications that are relevant for considering a product for safe traffic use are-
- Load Capacity: (AASHTO M306 Sect 6 or EN124)
- Material: applicable standards for materials (especially AASHTO M105)
- Labeling: (AASHTO M306 Sect 10)
- Resistance: UV (ASTM G154-06)
- Chemical (ASTM D543-06)
- Slip Resistance (ASTM C1028-07)
- Water Absorption (for Sanitary Sewer- ASTM D570-05)
- Impact (ASTM D2444-05)
- Flammability (ASTM D635-06)
- Wear resistance- abrasion test (ASTM C501)
While a “heavy duty” meter box and lid may pass the basic proof load test requirements of H-20, (proof load of 16,000 pounds on a 9 X 9 inch square pad for one minute) it may not stand up to the actual traffic situations of H-20 which includes cars and heavy trucks passing OVER the covers at high rates of speed. It also should support a 32,000 lb. dual spaced wheel load and live loads that produces as well. Most meter box lids are very thin (especially the plastic lids weighing only a few pounds) and they are not designed for traffic because they do not “sit down” far enough in the ring seat and they are just not heavy enough to prevent “popping up or popping out” after being driven over at road or highway speeds which can in some cases potentially exceed 70+ MPH OR MORE. It should also be noted that meter box locks (plastic or brass/bronze) were not designed for holding a cover down for traffic use. They were only designed “to keep honest people honest” and keep lids in place for meter service personnel and owners. Any brand of meter box lock would most likely fail very quickly if exposed to H-20 traffic conditions.
We recommend the BH® 380-24® ML “Water Meter” manhole ring & cover for light traffic use such as alley ways, parking lots, or drive ways. This product uses our BH® 400-24® D manhole ring, BH® 380-24®ML inner cover, and our BH-3PD® lid-9 locking ductile iron inner lid. The cast iron ring and the 2-1/2” thick by 24” diameter (140 pound) cover is machined in accordance with AASHTO M306 Section 5 and is H-20 rated, however, the 7/16” thick by 12-5/8” diameter ductile iron locking inner lid (13 pounds) is not machined due to the way it is designed. Therefore we cannot recommend it for H-20 roadways or highway traffic use, but it is fine to use for “light duty” traffic at low speeds such as in alley ways, drive ways, or parking lots.
For actual heavy duty H-20 traffic situations, we recommend using a manhole ring & cover. This gives you a machined ring with a machined cover of at least 2” thick. Examples- BH® 300-24® with a 2″ seat depth, the BH® 400-24® with a 2-1/2″ seat depth, or the BH® VRM-30® 30″ manhole with a 2″ seat depth. These manhole covers sit down far enough in the ring seat and are heavy enough to prevent “popping up or popping out” when being driven over at high rates of speed. They are machined in accordance with AASHTO M306 Section 5 and form a good seat “match” to prevent rocking, rattling, or vibrations and noise.
Noise mitigation for manhole castings used in H-20 should also be considered. Manhole rings and covers machined in accordance with AASHTO M306 Section 5 provide a near perfect match between the ring and cover and this prevents “rocking and rattling” when driven over in traffic. If the lid is not machined, it will “rock, rattle or vibrate” by sitting poorly on the seat of the ring. Unmachined meter box lids will rattle and will produce much unwanted noise if used in traffic, because the lids are thin and typically very loose fitting. The resulting noise levels can be very annoying and distracting to drivers, or can even create unpleasant noises that could result in complaints from residents, or cause accidents. This could be prevented by choosing the correct H-20 product in the first place.
When designing roads or highways noise mitigation has been addressed by federal laws and rules. The National Environmental Policy Act (NEPA) of 1969 provides for evaluating and mitigating adverse environmental effects which includes highway traffic noise. The Federal-Aid Highway Act of 1970 specifically involves abatement of highway traffic noise. This law mandates FHWA to develop noise standards for mitigating highway traffic noise. The law requires promulgation of traffic noise-level criteria for and further provides that FHWA cannot approve the plans and specifications for a federally aided highway project unless the project includes adequate noise abatement measures to comply with the standards. The FHWA has developed and implemented regulations for the mitigation of highway traffic noise in federal-aid highway projects. When designing any road or highway project, these rules should be considered. Title 23 of the United States Code of Federal Regulations Part 772 require the following during the planning and design of a highway project:
- Identification of traffic noise impacts; examination of potential mitigation measures;
- The incorporation of reasonable and feasible noise mitigation measures into the highway project; and
- Coordination with local officials to provide helpful information on compatible land use planning and control.
For the reasons stated above and our many combined years of experience in the industry, Bass & Hays does not suggest using any meter box or meter box cover for H-20 heavy duty traffic use UNLESS…
- the product is specifically identified as acceptable for H-20 traffic use by the manufacturer,
- the product has passed stringent accepted standards of testing for H-20 or better in accordance with AASHTO M306,
- the manufacturer’s warranty specifically covers the product for H-20 heavy duty traffic use and,
- the product is properly installed in reinforced concrete in accordance with current and accepted government, engineering, and industry standards, and with oversight by a licensed/certified engineer, inspector, or installer.
PLEASE TAKE NOTE: A traffic rated product is only as good as the installation supporting it. Products used for any traffic installation must be traffic rated products and must be properly installed using the appropriate type and amount of steel reinforcement and concrete and in strict accordance with current and accepted government, engineering and industry standards and by a licensed/certified installer with oversight and inspection by a licensed/certified inspector. (even most unincorporated areas have basic standards for traffic rating) If not properly installed, a traffic rated product cannot be designated as “traffic rated” even if it technically meets “traffic-rated” criteria and non-traffic products installed for traffic use are not “traffic rated” period, and both void the manufacturer’s warranty. This may result in failure, creation of poor road conditions, safety hazards, and accidents that could result in injury or death to occupants of vehicles.
BOTTOM LINE: Choose the right product for the job, and install it properly. Please use the contact form or call us for more information if you need a meter box for traffic situations, 1-800-258-2278 toll free.
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