In the first blog in this series, we discussed the story behind the CE mark, the Machinery Directive, and the associated requirements regarding the design, production, and sale of machinery bearing the mark. The second blog discussed a cornerstone of safer machine design, the risk assessment. This installment will discuss another crucial piece of the safety puzzle, machine guard design. (more…)
Hydraulic cranes absolutely rely on the integrity of their high-pressure fluid systems for safe operation. A crane can become out of level when an outrigger cylinder leaks over time, possibly leading to a tip over. A boom can collapse if a hydraulic hose ruptures. It is not possible to absolutely prevent hydraulic cylinders from developing leaks or prevent hoses from rupturing during the life of a typical crane, therefore crane manufacturers provide load holding valves at key components to prevent these dangerous incidents. In fact, ASME B30.5, Mobile and Locomotive Cranes, requires load holding valves or equivalent devices at outrigger cylinders, boom support cylinders, and boom telescoping cylinders. (more…)
In the previous blog (Part One) we discussed the backstory behind the two stylized letters CE and what it means to the design of machinery bearing the mark. We outlined some of the requirements of the “Machinery Directive” (MD) which include what are known as “Essential Health and Safety Requirements.” The Essential Health and Safety Requirements incorporate an iterative risk reduction process during design that takes into account (more…)
Ammonia is a compound consisting of one nitrogen atom and three hydrogen atoms and is denoted by the formula NH3. Its boiling point is -28°F at atmospheric pressure, so unless it is under pressure, it is gaseous at room temperatures. Therefore, pure ammonia is typically stored under pressure in a liquid form. Household ammonia is only 5-10% NH3, the remaining 90-95% is water. Ammonia is extremely soluble in water. It is often depicted like this: (more…)
Cranes are powerful lifting devices that we see everyday in construction areas, shipping terminals, and industrial sites. They are so common that we often pass by them with little thought. Cranes, however, can sometimes become involved in incidents that injure people or damage equipment. (more…)
An unfortunate and tragic case that we investigated involved a commercial “rollback” recovery truck that was being used to transport a four-wheel drive diesel pickup. The diesel pickup was not in running order with its’ engine in the bed of the truck. Consequently, a commercial towing company was hired by the truck owner to transport the truck. In the process of loading the truck onto the rollback, the truck came uncoupled from the winch and cable system. The truck then rolled down the inclined bed of the rollback, running over and killing a bystander. (more…)
Hail property damage is frequently reported after an HVAC service call. Building owners are often unaware there is damage until the power bill starts trending higher and the HVAC system is simply not cooling effectively. Take look at the fins! The National Weather Service reported over $722 million in property damage from hail in 2018. Based on NWS data, hail caused more property damage than tornadoes or thunderstorms. Only Tropical Storms/Hurricanes at $12 billion, coastal storms at $1 billion and flooding at $1 billion were more costly than hail to property.
One of the items very susceptible to damage is the HVAC system. The heat that is removed from the interior of a building must be rejected to the environment. As such the HVAC system is placed where it can have unhindered access to outdoor air in order to function properly. This often results in the unit being placed in a large open space such as a rooftop, making it susceptible to damage such as hail. (more…)
The Occupational Health and Safety Administration (OSHA) “Top 10 for 2018” violations once again have Machine Safeguarding earning a position on the list. Machine safeguarding was the 9th most cited standard as noted in the list below:
(Source: www.osha.gov/Top_Ten_Standards.html)
A mini-excavator at a job site developed a leak at a hydraulic fitting at the base of the cylinder that raises and lowers the boom. A subcontractor foreman at the site raised the boom to search for the leak. The foreman found and attempted to tighten the leaking fitting. When he did, the fitting separated from the base of the cylinder, releasing the hydraulic pressure that held the boom aloft. The boom fell and the bucket struck a nearby superintendent for the general contractor.
I recently worked on an interesting case involving a box baler. An employee of a butcher shop put some empty cardboard boxes in a vertical box baler and pushed the control switch to compact the boxes. After the 30 by 60 inch platen weighing 851 pounds returned to its raised position, the employee reached into the open space above the bottom door on the baler and began to clear cardboard from the bale tie slots in the bottom of the raised platen. Suddenly, and without warning, the steel pin attaching the platen to the raised hydraulic cylinder rod failed. The heavy steel platen fell and crushed his arm which was outstretched over the baler door into the compaction space.
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