WATER BAGS
Proof load test water bags
The age-old question within the lifting industry is the use of solid weights VS proof load test water bags. While there is use for both solid weights & water bags in the industry depending on the applications and site requirements, water bags are the more economical option when it comes to the inspection and load testing of larger lifting machinery. Some machines such as forklifts are only suited to testing with a solid test weight as the machine's load centre needs to be achieved and the test load cannot be under-slung as per SANS 10388. While there is use for both solid weights & water bags in the industry depending on the applications and site requirements - water bags are the more economical option. So the debate begins. Test weights or proof load test water bags? Cost-saving It is far more economical to transport water bags as opposed to solid test weights provided the application is right. As mentioned – forklifts and certain other machinery cannot be tested with water bags. If we look at the practicality with regards to the transportation – water bags make more sense. As a frame of reference to transport 70 tons of solid test weights will likely require three trucks and the logistical cost on that is astronomical, whereas the transportation of 70 tons of water bags is simple - 2x correctly rolled 42
Lifting Africa - May/Jun 2020
35-ton proof load test bags can be transported on a 1-ton light delivery vehicle or bakkie as we put it in South Africa. This means that we can achieve more competitive pricing as the logistic cost is lowered.
water will keep flowing and the load will increase – however the reading on the flow meter will not. If we look at Europe – Flow meters are no longer permitted to be used as there have been multiple incidents that have occurred whilst in use.
Going green. Now we know to be more conscious than ever when it comes to environmental issues and water saving methods. So how do we combat this?Simple – most sites have water treatment systems and we can pump the water back into the system to avoid wastage.
The function of a load cell is to measure mass or load and is, therefore, more suited to the application of load testing. One must remember it is essential for a load cell to be calibrated regularly to ensure accuracy.
With regards to port applications – seawater can be pumped from the port – provided the right pumps are used and the seawater is drained straight back into the ocean. Use of flow meters VS load cells While a flow meter is a cheaper option - one must take into account the function of a flow meter, which is to measure flow and not mass. Many factors could affect the reading of the flow meter for load test use. One factor is the viscosity of the water – basically the water density. Are you using clean water, dirty water or seawater? All factors play a role in the mass that will be applied. Now a flow meter only measures flow and not water density and therefore cannot be considered accurate. Another factor that could affect the reading of the flow meter is if the water is not clean and an object becomes jammed – such as a stone – the
Now let's talk price. The cost of water bags are very high as the materials used must be of the highest quality.The investment in water bags requires a lot of capital to procure these bags and the life spans depend on care, handling, frequency of use and material construction. Regular maintenance is also essential. It is not economical for some companies to purchase bags due to the capital required, however -there are a few companies such as ours - that offer water bag rentals and will gladly assist throughout Africa with rental solutions to suit the project. The rigging of Load Test bags. LMI's & LME's making use of load test bags must know how to rig them. It is also essential to note that the way bags are rigged could effect tonnage capacities if multiple bags are rigged together. The way bags are rigged could
