Concrete pumping improves productivity and safety on the jobsite by taking the most grueling manual labor out of a concrete pour. Reducing activities like wheeling and raking has prevented an uncountable number of back injuries over the years, not to mention increased the quality of the concrete. But concrete pumping isn’t risk free. Electrocutions and tip overs are two safety issues that can be prevented when workers follow proper pump setup procedures.
The right site
Concrete pump safety starts with a safe, uncluttered space for the pump truck on the jobsite. The ideal space will be level, large enough for the pump with extended outriggers and the expected flow of ready mix trucks, and away from power lines (more about that later) and excavations.
If the pump setup site is near an excavation, follow the one-to-one rule: For every 1 foot of vertical drop, stay back from the base edge at least 1 foot. Take measurements from the edge of the outrigger pad nearest the excavation. Less-than-ideal soil conditions and engineered support walls are treated differently, so check with the pump operator for guidance.
Proper outrigger procedures will drastically reduce the chance of a tip over on the job site. Tip overs are typically caused by either outriggers not having enough cribbing or surface area to properly support the unit, or in instances where the outriggers are not fully extended. Unknown factors, like underground voids, can also cause a tip over.
Soil type on the jobsite will factor into outriggers. Different soil types have different load-bearing capacities. For instance, virgin ground supports 22 psi while firm, compacted gravel supports 58 psi.
Cribbing is used to spread the weight of the load. When in doubt, always use more cribbing. Concrete pump manufacturers supply outrigger pads with their equipment, several companies sell after-market cribbing, and contractors often have jobsite materials like wood dunnage or flat steel plates available if additional cribbing is necessary.
When the pump operator sets the outriggers, the weight of the machine should be transmitted straight down. Do not set outriggers on uneven soil or a hill, and never bridge cribbing over a hole.
Before pumping, the operator should slowly extend the boom over each outrigger. This allows a contractor to see if the outrigger is sinking into the ground, which could cause the unit to tip. Additional cribbing surface area or other adjustments should be made if an issue arises.
When jobsite conditions prevent full extension of the outriggers, shortrigging might be necessary. Shortrigging should only be done on the side of the pump away from the pour. It involves its own set of guidelines and safety requirements. Never try shortrigging unless your operator is educated on the technique and responsible precautions are taken.
A boom coming in contact with power lines is the No. 1 cause of fatal accidents when using a concrete pump. The American Concrete Pumping Association (ACPA) says placing booms should never be operated within 20 feet of working power lines; this is known as the danger zone. It is a good idea to mark the danger zone with cones or other identifying markers.
Whether a contractor owns or rents the pump, he needs to be aware of any power lines near the jobsite and inform the pump operator and workers on site of the presence and location of these lines. Any time power lines are present, a pre-pour meeting should be held to discuss the pour and how to avoid the power lines. Everyone on the jobsite should be trained on power line and electricity safety, where the danger zone is, and the purpose of the danger zone. When power lines are in the boom movement area of the pour, a spotter must be employed whose only job is to warn the operator if the boom comes within the danger zone.