If you’re in the concrete pumping industry, then chances are you’ve dealt with, heard about, or otherwise been involved in a hose-whipping incident. Technically speaking, hose-whipping is known as “air ingression to the concrete pumping delivery pipeline.” In layman’s terms, hose-whipping is what happens when trapped air is momentarily compressed inside the end hose of a pumper and then suddenly released. The built up pressure causes the hose to whip violently, many times resulting in injuries to placing crew personnel. These injuries usually occur from the end hose striking the worker; however, flying concrete, rocks, or debris coming from within the hose can also result in significant injury to those in the general vicinity.
To understand how to avoid or reduce hose-whipping incidents, it’s first necessary to have a general understanding of how hose-whipping occurs. For a hose-whipping hazard to exist there needs to be three factors present:
- There must be air in the delivery system;
- There must be something pushing on the air;
- There must be restriction near the hose causing the air to compress.
If these three factors are present, it’s only a matter of time before the hose whips and debris starts flying. So the best way to prevent an incident is to disallow these three things from happening in the first place.
Typically, air enters the delivery system through one of a number of common ways including:
- When the delivery system is void of concrete; therefore full of air. This can happen when first starting or restarting after moving.
- The pump sucks air into the material cylinders through the hopper. This can happen when the pump is first started or the hopper goes empty during pumping.
- Air is introduced through the tip hose. This can happen any time the pump is operated in reverse or shut off during pumping with the boom’s tip section is generally facing downward.
- Air is introduced into the interior of the pipeline, other than at either end. This can happen when there are holes in the pipe, when gaskets are damaged, etc.
While there is certainly no sure fire way to prevent hose-whipping, there are definitely some steps that can be taken to reduce the risk.
- Wear PPE at all times when operating a concrete pumper.
- Make sure the boom tip is never facing downward when the pump is shut off.
- Know how air enters the delivery system and be prepared to communicate that knowledge to others on the jobsite.
- Know the telltale signs of a blockage.
- If a blockage is detected, move outside the end hose movement area.
As with most things in construction, education is a key component to remaining safe. Whether an operator, a laborer, a member of the placing crew, a ready-mix concrete truck driver, or a contractor, knowing the signs leading to blockages is crucial to staying safe and going home from work in the same condition you arrived there in.
*Allied does not deem this blog entry as a complete and thorough listing or overview of the above topic, and does not recommend it be primarily relied on. It only highlights some common issues and resolutions. For a thorough overview, please contact Allied’s Risk Engineering Division.