Heat stress types

Ultrasonic (processes) Process which utilizes specially designed tooling usually vibrating at 15-80 KHz. Processes are designed to cause localized heating of thermoplastic materials which, in turn, will provide some type of welded or fused joint. Benefits are elimination of fillers and minimized heat stress on surrounding materials. 

However, after becoming familiar with site hazards as best as one can, along with analytical data, the level of protection shonld be reexamined. This reexamination shonld be bnilt into the plan, and specific criteria for downgrading levels of protection or the type of protective eqnipment shonld be considered. Even a downgrade in the type of coveralls reqnired can make a large difference in worker heat stress load. The ability of tyvek to breathe (as opposed to saranex) is very desirable when considering worker comfort and heat load. These options, and when they become viable, shonld be anticipated beforehand and placed in the SSAHP. 

Other relatively inexpensive personal protective items that are not absolutely essential but should be considered are protective garments and gloves. One-piece coveralls with head covers and booties made from lightweight plastic such as Tyvek are relatively inexpensive, semi-repellent, and disposable. These types of suits are used in the nuclear and chemical industries to provide an added protection against contamination. Tyvek suits have sewn seams and are not recommended for chemical protection, except for vapors of low toxic solvents. Saranex-coated Tyvek or other heavy multilayer suits are required for long-term protection from chemicals. These heavier specialized suits significantly increase heat stress and should not be used by untrained personnel. 

An interesting illustration of the roles played by low-molecular-mass protein stabilizers in assisting cells to cope with heat stress is provided by work of Singer and Lindquist (1998a,b), who examined the complementary roles of the disaccharide trehalose and heat-shock proteins in recovery from thermal stress by the yeast Saccharomyces cerevisiae. Many types of yeast produce high concentrations of... 

The potential for heat stress is influenced by many factors, including ambient temperature, relative humidity, amount of sunshine, wind speed, amount and type of PPE, and the workload. 

When selecting the type and manufacture of the PPE, the purchaser should understand the functions being preformed by the responder and the chemical and physical hazards associated with the operation. They must also know how the operation and chemical will effect the degradation of the suit, gloves, and boots and the tactility and dexterity needed by the responder. Especially when Levels A and B equipment is in use, it is important not to overlook nonchemical hazards, such as heat stress, cold stress, slip, trip and falls, moving equipment, and lifting. 

ROS production is a common feature in responses to environmental stress.10 It has been demonstrated that heat-shock transcription factor, HsfA2, plays a crucial role in maintaining redox balance. 1 Using a ROS-specific probe and laser scanning confocal microscopy (LCSM), ROS production could be clearly monitored in situ. 0 Here, we used a DF technique combined with LCSM imaging to detect the responses of HsfA2 mutants and wild type (WT) plants to heat stress. 

A series of in vivo and in vitro experiments (see later) have demonstrated a functional cooperation between Hspl04 and Ssa proteins. The role of Hspl04 in induced thermotolerance in yeast is most apparent at longer exposures to extreme heat stress (Sanchez and Lindquist, 1990). At shorter incubation times, wild-type and 77SPi04-deficient strains sur-... 

M. Nonchemical physical exposures in the workplace are important because they can cause systemic effects that mimic chemical toxidromes. The most important example is heat stress, which is a major occupational health issue. Other relevant nonchemioal, work-related physical exposure types include ionizing radiation, nonionizing radiation (such as ultraviolet, infrared, and microwave exposure), and increased barometric pressure (eg, among caisson workers). Except for extremes of exposure, the adverse effects of these physical factors are generally associated with chronic conditions. 

Extremes of either heat or cold can be more than uncomfortable—they can be dangerous. Heat stress, cold stress, and burns are major concerns of in the processing industry. Employees who work outside during the summer on surfaces that heat up and store heat will get very hot. They will be around metal equipment and vessels that are hot and radiate large amounts of heat. The opportunity for heat stress will be present. Also, winter conditions on a processing unit in Colorado or Alaska will present the opportunity for frostbite or hypothermia. The prudent process employee will seek to understand the types of heat and cold stress and how to avoid them. 

The most common types of heat stress (see Figure 9-1) are heat stroke, heat exhaustion, heat cramps, heat rash, transient heat fatigue, and chronic heat fatigue. These various types of heat stress can initiate a number of undesirable bodily reactions, some very serious, including prickly heat, inadequate blood flow to vital body parts, circulatory shock, and cramps. 

Heat stroke is a type of heat stress caused by a rapid rise in the body s core temperature. It is very dangerous and can be fatal. First aid should be rendered immediately. Heat stroke s symptoms are (1) hot, dry, mottled skin, (2) confusion and/or convulsions, and (3) loss of consciousness. In addition to these observable symptoms, the victim will have a rectal temperature of 104.5°F or higher. 

Heat exhaustion is a type of heat stress caused by water and/or electrolyte depletion. A victim of heat exhaustion may have a normal or even lower-than-normal oral temperature but will typically have a higher-than-usual rectal temperature (i.e., 99.5°F to 101.3°F). Heat exhaustion is caused by prolonged exertion in a hot environment and a failure to replace the water and/or electrolytes lost through sweating. Heat exhaustion causes the body to become dehydrated, which decreases the volume of circulating blood. The various body parts compete for a smaller volume of blood, which causes circulatory strain. A victim of heat exhaustion should be moved to a cool place and made to lie down. Replacement fluid containing electrolytes should be taken slowly but steadily by mouth. 

Heat Cramps— A type of heat stress that occurs as a result of salt and potassium depletion. 

Heat Rash—A type of heat stress that manifests itself as small raised bumps or blisters that cover a portion of the body and give off a prickly sensation that can cause... 

According to the OSHA Technical Manual, which prescribes workloads for workers under temperatures typically experienced outdoors during the summer months, to keep from exceeding the Threshold Limit Value (TLV) when the ambient temperature is above 86° F, the work regimen will consist of 25 percent work and 75 percent rest. This type of schedule plays havoc on productivity, as does the lost time incurred when a worker succumbs to heat stress. Plus, as workers become fatigued by back-to-back days — where each day they approach their TLV — their quality of life diminishes. That affects productivity and causes a rise in sick days. 

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