Why Choose Water Bag Proof Load Testing Over Traditional Solid Weights?

Water-filled proof load bags are designed to replace traditional solid weights and ensure workers’ safety at a job site. These bags are now used extensively due to their practicality, economy, and safety features. Moreover, certain proof load testing becomes feasible only by using water weights.

Using water bags prevents the crane from being shock-loaded and averts any damage resulting from malfunction. This is because you can increase the load in water bags gradually by increasing the water flow. In case any issue is detected, it’s easy to stop filling the bags and drain them to avoid failure of the entire system.

This post aims to shed light on how water-filled weight bags are redefining proof load testing and why they are becoming integral in heavy industries.

A. Why Choose Water-Filled Weight Bags?

Water-filled weight bags have been approved worldwide as an effective means of crane load testing. The bags are easy-to-use and offer safe crane load test weight solutions for load testing all types of lifting equipment. They are usually manufactured with premium quality PVC coating and fabric, and comply with the LEEA 051 guidance.

The best thing about water-filled weight bags is that water can be poured gradually and precisely. This allows you to identify issues with the lifting equipment, even before the maximum load weight is reached.

The design of these bags facilitates seamless proof load testing without the use of solid load test weights. Considering the safety and ease-of-use these bags offer, water-filled weight bags are now used for proof load testing newly-built structures, and for lifting equipment, and performing periodic checks or maintenance.

B. Key Characteristics of Water Bags

Water bags offer a quick and safe way to test loads. Here are some of their notable characteristics:

1. Quality Fabric

Water weights bags are manufactured with heavy-duty PVC coating fabric. The material used is highly flexible and resistant to heavy loads. The bags are filled with water until the desired weight is obtained. The high-resistance fabric ensures a safe test without the bag getting damaged.

2. Greater Safety

The unique design of water-filled proof load test bags makes them a great substitute to traditional solid weights and ensures workers’ overall safety. It enables a safer approach for load testing cranes, beams, and davits, and ensures adherence to OSHA regulations for crane overload tests.

3. Higher Efficiency

Water weights bags are easy to use, and require minimal training and safety measures. This translates to higher efficiency and productivity of the load testing team. Moreover, the heavy-duty webbing harness facilitates easy lifting of loads with minimal effort, improving the speed of the overall testing procedure.

4. Economical Option

Water weights bags are way more economical to operate than traditional solid weights. Their standard assembly includes shackles, elastic string, webbing straps, round sling, and end shackles. Unlike solid weights, they don’t require any complex equipment to operate.

Further, transporting water bags is cheaper compared to solid test weights. A light delivery vehicle is sufficient to transport proof lest test bags up to 70-tonne, whereas solid weights may need three trucks for the same load.

5. Customized Solutions

Load test water weights bags offer a wide array of load testing capabilities, ranging from 1 ton to 100 tones. You can also opt for customized size and capacity to suit every unique need at your job site. All you need to do is, specify the size and load testing capabilities, and place an order with your preferred manufacturer. However, care should be taken that your chosen manufacturer abides by all OSHA guidelines.

Load test water weights bags with load weight less than 100 tones use a single water weight load test water bags, whereas those over 100 tones use several water weight load test water bags together to perform load testing.

6. Flexibility and Resistance

Water weights allow flexibility during crane load tests. You can gradually increase the loads in the water bags and identify potential problems before reaching the maximum load. Further, water bags for crane load testing are made of high tensile coating fabrics, equipped with master links, shackles, lifting belts. All these factors make them less prone to damage due to excess crane test weight during load tests.

C. How to Conduct Proof Load Testing with Water Bags?

Proof load test water weight bags are designed so that the lifting set is separate from the water bag body. This implies that damage to one webbing element will not result in the failure of the entire system.

At Holloway Houston, INC, we have a team of trained technicians who are thorough with the entire process of performing load testing with water bags. Our water bag testing program offers a safer, economical, and relatively faster alternative to solid weights for proof testing cranes. Here’s a step-by-step guide on how we perform load test with water bag:

1. Before Load Testing

Before load testing, you need to verify that the crane’s hook is working at its maximum potential.

If you intend to use a single hook, make sure you have load cell, shackles, water weight bags, filling and discharge hose, pulley, and a rope. But if you’re using a double hook, ensure that you have a sling.

Having said that, you also need to ensure that no sharp items are present on the site, as they can damage the bags and result in water leakage.

2. Operation of Load Testing

If you are using a crane with a single hook, you need to properly connect the shackle, load cell, and water bag. Once you have securely attached them, set up the water filling and discharge the hose. Next, install a pulley and rope on top of the water bag.

If your crane has a double-hook, put the sling between the hook and shackle. This will help the second hook lift weights in proportion with the first one.

To lift the load, open the load cell and start lifting the water bags. As the crane lifts the load off the ground, ensure that there is no friction between the bottom of the water bag and the surface. When the entire load is off the ground, you can start filling water into the bag.

Finally, close the valve on the discharge hose and connect the filling hose to the water supply. When the weight of the water bags reaches the load required to be tested, stop filling water into the bag.

3. After Load Testing

Put down the discharge hose and open the ball valve to let the water out. After the water is completely drained, pull down the discharge hose of the weights bag. Ensure to pull down the filling hose, load cell, and shackles.

D. Safety Rules for Using Water Load Test Bags

When using water load test bags, it’s essential to abide by certain safety parameters. Here are a few rules that you must follow:

  • Read the instruction manual thoroughly before using the bags.
  • Ensure that there are no signs of cuts, abrasions, or cracks on the outer skin of the water test bag.
  • Don’t drag the bag on the ground or walk/roll over it.
  • Make sure to never exceed the set capacity of the water test bag.
  • Always use only water to fill the water test bag.
  • Do not use the water bag outdoors when the wind speed exceeds 30 km/h.

E. How to Use Water Test Bags?

Here’s how you should use the water test bags to ensure that they always operate at their highest potential:

  • Always unfold the water test bags on a carpet or cardboard.
  • Ensure to connect the drain hose to the water test bag and close the valve.
  • Make sure to fill the water test bag through the upper inlet and avoid the formation of creases at all costs.
  • Never exceed the maximum capacity of the water load test bag.
  • Make sure to empty the bag by opening the bleed valve after the load testing.

F. Advantages of Using Water Bags for Proof Load Testing

Here are a few advantages of using water bags for proof load testing:

1. Can Be Rolled up and Packed into Containers

Since water bags are made of lightweight, pliable fabric, they can be rolled up and packed in containers easily. This considerably reduces the transportation cost to a worksite. Usually, the packaged weight of water bags is about 1% of their weight when filled with water.

2. Test Loads Occurs Gradually

The application of test loads occurs gradually as the bag is filled only with load water. This helps prevent shock-loading and allows early identification of technical issues.

Moreover, the operator can perform the proof-load testing using immediate hold points and test the hoisting/ braking capability of equipment even before reaching the designated test load.

3. Infinite Number of Test Loads

Proof load water bags help in the accurate selection of test loads. You can use force dynamometers or water meters to alter the weight of the loads. This allows for an infinite number of test loads to be achieved to meet the unique requirements of each equipment.

4. Ease of Transportation

Proof load water bags are compact and can be easily transported by pick-up trucks and small commercial trailers.

5. Most Organization Trust It

Water bags are certified for load testing by all major organizations in the United States. The Occupational Safety & Health Administration, American Bureau of Shipping, and other organizations have approved these bags as safe to use.

6. No Need to Lower the Test Load

You can release the test fluid by simply draining water from the water bags. There is no need to lower the test load in hazardous areas.

G. Storage and Maintenance of Water Weight Bags

It is crucial to ensure proper storage and maintenance of water weight bags for their optimal performance. Here are a few guidelines in this regard.

  • Always store the water test bags in a flattened manner.
  • Ensure that the storage room’s temperature is between -5°C and +20°C and there is a degree of hygrometry between 40 and 70%.
  • Keep the bags away from sunlight.
  • Clean the bags with warm soapy water after each use (never use chemicals, iron brush, or high-pressure wash). Then, rinse and let them dry.
  • Check that the bags are not damaged (cracks, exposed cloth, cuts) before each use.


Water weight bags are easy to use and serve as a safer option to traditional weights. These bags are made of premium quality PVC and have a physically proven safety factor of over 6:1. They are also proof load tested to over 2:1.

The best thing about these bags is that technicians can easily identify problems before attaining maximum load, thereby preventing damage to equipment or causing injury to workers.

The above guide should help you understand why using water weight bags makes perfect sense for proof load testing, and why they’re better than traditional steel weights.