The Truth About Hydrovac Weights

The Truth About Hydrovac Weights

As posted on Hydrovac Nation
Written by Benjamen Schmitt, Product Manager at Vactor Manufacturing

Say the word “weight” around a hydrovacer, and see what reaction you will get. Weights of hydrovacs are becoming the number one issue for our customers and the hydro excavation market. Customers are looking to carry as much material as possible while staying within the weight regulations in their area. Hydrovac manufacturers are beginning to spread misinformation with regards to weights and regulations. You will see catch phrases such as, “Lightest unit in the industry”, “Fill the truck with debris and not be overweight”, “Carry a full load without exceeding the GVWR”, or “The only scalable unit on the market”. While these catch phrases are great for catching the reader or customer’s attention, they are all misleading and do not properly educate the customer.

Weight enforcement has increased significantly on hydrovacs in recent years. This increased focus is due to several reasons. One driver is the boom and eventual slow down of the oil and gas industry. In the oil and gas industry, hydrovacs typically worked off-road or on lease roads where weight compliance was not required. During the oil boom, there was a significant amount of hydrovacs working in these locations; however, as the industry slowed down, these hydrovacs began targeting other industries, such as utilities and municipalities, where the work was now primarily on state and local roads. Because of that, these hydrovacs are now working where weight compliance is a necessity and their units were not designed to maximize payload capacity. Additionally, hydrovac weight tickets can be significant, with some tickets over $20,000. Because of this, focus on hydrovacs has increased due to the revenue their overweight tickets generate. I once had a customer tell me the local weight enforcement officer told him, “We know all hydrovacs are overweight and pull every one over we see”. I have also witnessed roadside checks at entrances to landfills and other known hydrovac spoil disposal locations.

Furthermore, Ontario Canada, where hundreds of hydrovacs work daily, recently passed a regulation change that will significantly affect hydrovacs in this area. Essentially, in Ontario, hydrovacs are classified as road building machines (RBM) which meant these hydrovacs did not fall under the same weight regulation requirements as other straight truck equipment in the area. Because of this, hydrovac operators in this area have been accustomed to hauling full truckloads to dump sites, which can sometimes be a 4-hour round trip. However, the Ministry of Transportation recently passed changes to the Highway Traffic Act that will classify hydrovacs as commercial motor vehicles (CMV) and require them to comply with all weight regulations, including weights. This change will take effect July 1st of this year and has the hydro excavation industry in this area on guard. Once July 1st arrives, hydrovac operators will become targets for compliance enforcement.

As a result, hydrovac manufacturers are beginning to market around weights. Unfortunately, much of the marketing information is incorrect or misleading information. There are many things to take into consideration when talking hydrovacs and weights:

What type of material is being loaded?

•  I have seen several statements made in the industry of “never get another weight ticket” or “only scalable hydrovac on the market”. What do these statements mean? In reality, nothing. Notice that these statements do not mention what the material is or how much the material weighs. Are they loading the truck with feathers, bricks, mud, water, etc.? Every material has a different density. We typically use 2,500 to 3,000 lbs per cubic yard of material for hydrovacs, which equates to 12 lbs/gallon to 15 lbs/gallon. For reference, water weighs approximately 8.3 lbs/gallon and dry dirt from 8.6 to 10.7 lbs/gallons. I jokingly say all hydrovacs are shipped fully legally fully loaded with air.

How much water is left in the water tank?

•  There are many hydrovac designs on the market – water tank in front of debris, water tank around the debris tank, water tank under the debris tank, etc. While this would seem insignificant, it is actually very important. There typically is 100 to 200 gallons of water remaining in the water tank when transporting to the dumpsite for washing out the debris body and cleaning the unit. These 100 to 200 gallons in the water tank is approximately 830 to 1,660 lbs of weight on the unit. This additional weight can shift the overall weight distribution of the unit dramatically, and must be accounted for in the weight distribution of the unit. Westech Vac Systems recently released a great animation of weight distribution with the launch of the Westech Wolf that illustrates how different water levels can shift weight around the chassis.

What are the regulations in your area?

•  Knowing the weight regulations in your area is extremely important when selecting a hydrovac and maximizing payload capacities. There are many different regulations to follow such as Federal Bridge Law, state/provincial laws, frost laws, and thaw restrictions. In addition to the regulations, it is also important to know how many axles are recognized in the state and if a lifting axle (such as a pusher or tag axle) are recognized in your location. Some locations in the U.S. and Canada, for example, do not recognize lifting axles when determining weight capacities of the unit. It is also important to understand the axle spacing because significant weight advantages can be had by spacing the axles at the optimal distance.

•  With Ontario’s weight regulation enforcement of hydrovacs, many competitors are beginning to market their products as “SPIF compliant”. What does this mean? As mentioned before, literally nothing. Ontario has the term Safe, Productive, and Infrastructure Friendly (SPIF) regarding chassis axle configurations. The goal of SPIF is to have chassis designs that are productive while reducing wear and tear on roadways. A SPIF chassis is any chassis listed on the Ministry of Transportation’s vehicle weights and dimensions sheet. Simply saying “SPIF compliant” means the chassis configuration is listed with which there are currently seven straight truck configurations. This statement would be similar to saying a chassis is “Federal Bridge Law compliant”. What is important is to understand how well the manufacturer understands the weight regulations in your area and how they can best tailor a product to best maximize payload.

•  Most manufacturers typically design their equipment around the Federal Bridge Law, which is the weight regulations based on number of axles and spacing of those axle when traveling on federal highways. However, when off federal roads, state, county, and municipal weight restrictions apply. Weight restrictions vary greatly in some areas between each jurisdiction. This variation is due to the different specifications of road construction. These laws can often be very specific as well – specifying different weight capacities depending on tire size and tread contact with roadways. Many of these laws, especially with SPIF, require a minimum percentage of the weight on the chassis’ front axle to ensure safe drivability. Shifting weight designs as mentioned above can be problematic in this area, and can often require a minimum level of water in the water tanks to maintain the minimum percentage. It is crucial that the hydrovac manufacturer understands these requirements to ensure they are specifying a chassis properly to meet these requirements.

What is the truck plated to?

•  When looking at weights, it is important to understand what the truck is plated to. When weight enforcement officers are checking a truck for weight, they are looking at several things. They are first measuring the axle locations and spacing that then is checked with their weight chart (state, federal, municipal, etc.). After this check, they may then check the tire ratings, the axle ratings, etc. They will also check to see what gross vehicle weight rating (GVWR) the chassis is registered. Just because the GVWR is rated to a higher number or Bridge Law allows more weight, you are limited to the GVWR to which the vehicle was registered. Exceeding the plated rating while staying within local weight regulations will still result in a weight ticket.

•  It is also important to understand what permits are available in your area. Some areas allow overweight permits for small fees for the entire year. Other areas allow permits based on a single trip, but those can be more cumbersome. Other locations have permits based on the type of vehicle – sewer cleaners for example have different regulations in Illinois than other straight trucks.

What is the chassis GVWR and the individual axle ratings?

•  It is important to know the chassis’ GVWR and the individual axle ratings regardless of the weight restrictions in your area. As an example, a single axle truck is allowed 20,000 lbs on the front and rear axles per Federal Bridge. However, most singles axle units have axles rated below 20,000 lbs for various reasons such as CDL requirements and Federal Excise Tax (FET). It is important to understand how the manufacturer of the hydrovac has distributed weight on these axles to ensure you do not exceed the operating levels of the chassis. Additionally, many larger hydrovacs have axles rated for capacities higher than allowed by state or federal weight restrictions because these units are often overloaded or utilized off-road where weight restrictions do not exist. When a manufacturer says, “Carry a full load without exceeding the GVWR”, while important, does not mean you will not get an overweight ticket when driving on roadways. For example, most tandem axle hydrovacs have a rear axle rating between 40,000 lbs and 46,000 lbs, but federal bridge law limits this axle group to a maximum of 34,000 lbs. Driving around with 46,000 lbs on the rear axle, while within the chassis design limits, will result in a significant overweight ticket.

•  It is also important to understand the weight ratings of other components on the chassis such as the chassis frame, suspension, and tires. A chassis GVWR is based on the lowest rated component in the system. You will want to make sure your equipment supplier has not cut corners with other components in the system when specify their chassis. When we specify a chassis, we typically beef up other components beyond the axle ratings to ensure a long lasting and durable product.

Many items go into understanding weights, weight distribution, and how much your hydrovac can legally haul. When you see comments such as, “never get another overweight ticket”, do not fall for the propaganda and start asking some questions.


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