Hazard, risk, and harm are terms that are used in the world of machine safeguarding. How do these words shape the concept of machine safeguarding? Let’s look a little deeper….
Hazard, which Merriam-Webster defines as a noun, lists its first meaning as a source of danger.
1: a source of danger
2a: the effect of unpredictable and unanalyzable forces in determining events : CHANCE, RISK
Previously, Warren posted the first installment of a series on losses associated with heating systems. The first article looked at central forced air furnaces. This new article will look at a common form of supplemental or secondary heat, oil filled electric radiant heaters. These heaters are commonly used to provide extra heating in areas that are lacking in central heating capacity. Another rationale for their use arises from manufacturer’s claims that the portable heating units can lower your power bill. This is based on Read More
An unexpected severe winter freeze will remind many people and businesses that when water in a pipe freezes, the ice will expand and burst the pipe or pipe fitting. Large losses will result from flooding when the temperatures rise. Insulation will help, but not prevent freezing. Insulation simply slows down the rate of heat loss. The time of exposure to subfreezing temperature is an important factor.
The American Society of Refrigeration and Air Conditioning Engineers (ASHRAE) Handbook of Fundamentals has a short entry on the topic (Chapter 23, page 23.5-6), which gives an equation for estimating the time that it will take an insulated pipe to freeze, Read More
“On average, U.S. fire departments responded to a highway vehicle fire every 182 seconds,” according to the NFPA’s Fire Loss Facts Sheet.
The National Fire Protection Association (NFPA) says that vehicle fires account for about 20 percent of all reported fires. Before I attempt to examine a vehicle fire loss, I like to check various consumer and government agencies websites to see if I can find any recall or historical data that might be important. This is true for heavy truck fires all the way to automobile and motorcycle fires. Read More
Temporary wiring is just that….temporary, and is typically used for repair and maintenance projects. In this blog I am going to discuss guidance offered by Article 590 of the National Electric Code (NEC), as well as some points to consider when using temporary wiring, including extension cords and holiday lighting.
Before each use, extension cords need to be inspected for visual damage. Cords with cuts or splits to the insulation need to be discarded. Cords with damage to the connectors, including those that feel loose when connected, need to be taken out of service. Failure to properly select and use extension cords can have a catastrophic result. Read More
This is the second in a two-part blog series about conveying equipment that severely injured a worker at a mine. In case you missed it, click here to read Part 1 where I describe the incident and the mining equipment. In this part, I will discuss my engineering analysis of the incident and the machinery involved and share the conclusions I reached.
The injured miner was a front-end loader operator. He was not a maintenance worker. He simply responded to a radio request for help with the conveyor. Power to the electric conveyor motors was locked out, but none of the maintenance workers did anything to lock out or block the hazardous gravitational potential energy in the heavy load of stone on the belt. Read More
This is the first of a two-part blog series describing an incident involving conveying machinery that seriously injured a miner. Part 1 describes the machinery and the incident. In Part 2 I will summarize my engineering analysis of the incident and share the conclusions I reached.
A loaded, inclined conveyor belt may contain hazardous levels of energy due to gravity. To protect workers, anti-reverse devices called backstops are installed on inclined conveyors to prevent unexpected downhill movement. The Conveyor Equipment Manufacturer’s Association (CEMA) defines a backstop as: Read More
Heavy machinery fires are often caused by hydraulic hose failures. Pressurized hydraulic fluid escaping from a failed hose assembly can be atomized into a fine spray that can be ignited by heated engine surfaces such as the engine exhaust or turbocharger.
Hydraulic hoses near the engine compartment of an excavator that burned.
Hydraulic hoses often fail due to age and wear, requiring regular inspection and replacement of hydraulic hoses to prevent failures. Hoses may also fail if they are misrouted. Misrouting can lead to the hose being pinched or causing it to chafe against a sharp metal surface. Read More
This is a case study about an incident I investigated involving a major upset in a distillation column. This blog builds on the previous blogs about the Distributed Control System, DCS – Data is the Key.
Distillation is a method of separating mixtures of compounds with differing boiling points. Uncle Bill with his still on the hill separates ethanol, that boils at 173°F, from water that boils at 212°F. If the mixture is heated to above 173°F, but below 212°F, the ethanol will boil, the vapor will travel up out of the unit and then can be condensed and served over ice with an olive… Any mixture of two or more chemicals with different boiling points can be separated in this way. The distillation Read More
Surge Protective Devices (SPD), formerly known as Transient Voltage Surge Suppressors (TVSS) have been around for a long time. The most recognized version is integrated into outlet strips and used to protect sensitive electronics from surges, or higher than expected voltages on the power line. Early versions of these surge strips were known to have problems where internal components could overheat and cause a fire. Thermal protection was added to the designs to greatly reduce the potential for a fire hazard. Such an implementation in an outlet strip is considered a Type 3 SPD. Read More
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