Minnesota Department of Corrections

 

 

AUTHORITY:           Minn. Rule 5205.0110

 

PURPOSE:     To establish a process for the prevention of heat related illnesses, cold weather exposure, and protection from severe weather.

 

APPLICABILITY:    All facilities, Sentence to Service (STS), and Institution Community Work Crew (ICWC).

 

POLICY:       Each applicable unit/facility will establish a safety program (Instruction) that establishes guidelines for the prevention of heat related illnesses, cold weather exposure, and protection from severe weather.  Each applicable unit/facility will develop instructions to implement this policy.

 

DEFINITIONS:

Heat cramps - commonly result from performing hard physical work in a hot environment. These cramps are attributable to the continued loss of salt that occurs in sweating.  Cramps often occur in the muscles used during work and can be alleviated by resting and drinking water.

 

Heat exhaustion - symptoms are headache, nausea, vertigo, weakness, thirst, and giddiness.  Workers suffering from heat exhaustion must be removed from the source of heat and provided fluid replacement along with adequate rest.

 

Heat stroke - occurs when the body's system of temperature regulation fails and the body's temperature rises to critical levels. The primary symptoms are confusion; irrational behavior; loss of consciousness; convulsions; a lack of sweating usually); hot, dry skin; and an abnormally high body temperature (a rectal temperature of 41 degrees C (105.8 degrees F).  If the body temperature rises too high, death will follow. The elevated metabolic temperatures caused by a combination of work load and environmental heat load, both of which contribute to heat stroke, are highly variable and difficult to predict.

 

Heavy work - rapid-paced or repetitive jobs.  Examples include shoveling sand, carpenter sawing by hand, heavy assembly work, and pushing, pulling, or carrying heavy objects repeatedly.

 

Light work- primarily standing or sitting while working.  Examples of light work include using a table saw, light assembly work, packaging operations, and using a riding mower.

 

Moderate work - increased levels of body movement, usually this will include walking or frequent arm movement.  Examples of moderate work include scraping paint, lawn mowing with a push mower, and raking.

 

Radiant heat - energy in the form of electromagnetic radiation that is transformed into heat when it strikes an object.  Radiant heat exchange is a function of the differential between the temperature of the skin and temperature of the surrounding surfaces.  Radiation does not heat the air it passes through. For example, the heat from a boiler or from the sun will transfer to (or heat) objects in their surrounding areas, but not the air itself.

 

Heat index – An index that describes what the temperature really feels like. It is a composite of the effects of temperature, wind, humidity, sunshine intensity, cloudiness, precipitation and elevation on the human body.  The index can be accessed on the National Weather Service Website at: http://www.crh.noaa.gov/pub/heat.htm.  Type in your zip code to see the current days conditions. 

 

Wet Bulb Globe Temperature (WBGT) - temperature reading taken with a special thermometer measuring 3 different aspects of the conditions.  These three readings are then correlated to an index that indicates what the actual temperature feels like to the human body.

 

Work modification - includes increasing the amount of breaks and assuring provision of readily available fluids.

 

PROCEDURES:

A.        Staff Training

1.        Training is required for those staff needing to determine weather conditions and decide on course of action for the offenders/employees

2.        Training must include the following topics:

a)        Knowledge of the hazards of heat stress

b)        Recognition of predisposing factors, danger signs, and symptoms

c)        Awareness of first-aid procedures for and potential health effects of heat stress

d)        Employee responsibilities in avoiding heat stress

e)        Use of protective clothing and equipment

f)        How to access and read the heat index

g)        Procedures for response to severe weather alerts

 

B.        Work Breaks

1.        The following guidelines are based on American Conference of Governmental Industrial Hygienists (ACGIH) data and must be used to determine when work modification in the form of increased breaks to allow for fluid replenishment be enacted.  The heat index is the reference for this data:

a)        86 degrees or higher for heavy work

b)        88 degrees or higher for moderate work

c)        90 degrees or higher for light work

d)        If the heat index is above 96 degrees, only essential work functions other than light work must take place outdoors.

2.        For a, b, and c above, at least 20 minutes of each 2 hour period must be used to allow employees/offenders to rest and drink fluids in an indoor area or shaded outdoor area.

3.        These guidelines apply only to the individuals performing the work, not to those who are observing or supervising the work in the same conditions.

4.        The above guidelines for increased breaks and provision of fluids apply to outdoor.

5.        Work areas with sources of radiant heat (laundry, boiler rooms, kitchens, etc.) can be measured (WBGT) upon request to determine if they meet these requirements.  In addition, supervisors in these areas must also be aware that because of radiant heat sources, it may be necessary to take the same precautions when the WBGT is lower than the temperatures stated above.

 

C.        Recreation/Yard Activities

1.        The above “Work Break” guidelines apply only to staff and offender work activities involving physical exertion.

2.        The yard may remain open and organized activities, such as softball, may take place since offenders voluntarily take part in these activities and it would be considered light work by ACGIH standards.

 

D.       Recommended Controls for Prevention of Heat Related Illnesses

1.        Engineering Controls - Fans, air cooling/conditioning, insulation and shielding must be implemented when feasible to reduce external sources of heat loading in work areas.

a)        Ventilation

General ventilation is used to dilute hot air with cooler air (usually cooler air is brought in from the outside).  This technique, which relies on the principle of convection, does not work as effectively in the hotter climates.

b)        Air Conditioning

(1)       Air conditioning reduces the temperature of the air by removing heat and humidity from air.  The two main types are refrigerated and water cooled systems.

(2)       Portable and/or local air cooling can be effective and more practical at reducing air temperatures in small, specific areas.  Cool room enclosures, can be used to enclose hot work areas or recovery areas near the job; for portable application a blower with built-in air cooling can be used.

c)        Convection

(1)       Changes in air speed using fans may help workers stay cooler by increasing both the convective heat exchange and the rate of evaporation.  The increase in air currents must directly impact the worker to be effective.

(2)       If the temperature is higher than 95 F, the hot air passing over the skin may actually make the worker hotter and offset any evaporative cooling.  Increases in air speed have no effect on workers wearing vapor-barrier clothing.

d)        Insulation

Insulating hot surfaces, and/or substituting alternative materials that minimize surface heat loads may reduce heat conduction.

e)        Shielding

(1)       Shielding may be used to reduce radiant heat by interrupting the flow between the source and the worker. Polished surfaces make the best barriers, although special glass or metal mesh surfaces can be used if visibility is a problem. Shields will not interfere with airflow and must be kept clean to maintain peak effectiveness.

(2)       With some sources of radiation such as heating pipes, it is possible to use both insulation and surface modifications to achieve a substantial reduction in radiant heat.

 

2.        Administrative Controls

a)        Acclimatization

(1)       Acclimatization reduces heat stress by increasing the performance of the cardiovascular system and efficiency of the body’s cooling system.  This results in the ability of the worker to maintain normal body temperature in these extreme environments.

(2)       An acclimatization program decreases the risk of heat-related illnesses and unsafe acts by gradually exposing employees to a hot work environment for progressively longer periods.  For workers with prior exposure to hot job environments, the regimen should be 50 percent exposure on day 1, increasing to 100 percent exposure by day 4.  For new, unacclimatized workers, the regimen should be 20 percent on day 1, with a 20 percent increase in exposure each additional day.

 

b)        Fluid Replacement

(1)       Workers must be provided with cool (50-60 degrees F) water and encouraged to drink frequently (one cup every 15 - 20 minutes or about 1 quart per hour). Water must be placed close to the work area for easy access.  All sources of water must be changed out on a periodic basis (at least daily).  Water sources kept outside must be filled with ice.

(2)       Salt supplements are not necessary when working in hot environments.  A normal diet has sufficient quantities of salt to maintain the proper balance.

 

c)        Work Practices - The following work practices must be considered for reducing heat stress:

(1)       Schedule hot jobs for the cooler part of the day.  Schedule and repair work in hot areas for the cooler seasons of the year (where possible).

(2)       Reduce the physical demands of work such as lifting of heavy objects or manual digging.  Mechanical assists must be implemented when feasible to reduce work loads and internal metabolic heat production

(3)       Rest/Recovery areas must be provided, e.g. air-conditioned areas, umbrellas, tents.

(4)       Intermittent rest periods with water breaks

(5)       Use of relief workers

(6)       Use of worker pacing

(7)       Assignment of extra workers

(8)       Provision of chilled water at worksite

(9)       Limit number of workers in confined or enclosed spaces, and use mechanical ventilation if needed

 

d)        Personal Protective Equipment - PPE such as respirators can significantly increase heat stress.  Therefore, heat stress factors must be taken into account when recommending PPE.

PPE to help alleviate heat stress can include reflective clothing, ice vests, wetted clothing, water cooled garments, etc, and must be evaluated for effectiveness for various activities.

 

E.        Responsibilities

1.        Supervisors must

a)        Be knowledgeable about heat stress and its effects.

b)        Be aware of the potential for heat stress when assigning job tasks.  Consider the following when evaluating job assignments for potential heat stress problems:

(1)       Work climate

(2)       Job intensity

(3)       Job duration

(4)       Acclimatization

(5)       Physical fitness

(6)       Work attire / PPE

 

2.        Safety officers must

a)        Be available for heat stress prevention guidance/consultation

b)        Be available to perform heat stress evaluations and recommendations including

(1)       Wet Bulb Globe Temperature (WBGT) measurements

(2)       Engineering control implementation

(3)       Personal Protective Equipment (PPE) recommendations

c)        Recommend appropriate work rest schedules for individual jobs

d)        Implement/administer heat stress training program.

e)        Administer heat stress program

 

3.        Employees must

a)        Be aware of the potential for heat stress when performing job tasks.

b)        Contact site supervisor, Health Services and/or safety officer for heat stress guidance

c)        Follow all safety procedures (as specified by your supervisor) including:

(1)       Work/rest periods

(2)       Appropriate work attire

(3)       Fluid maintenance

(4)       Sun shades

 

F.        Cold Weather Considerations

Whenever the ambient air temperature is at or below 0 degrees Fahrenheit or the wind-chill is at or below -5 degrees Fahrenheit, the watch commander may cancel all or portions of offender outdoor activities.  Essential work duties will continue as required.  Staff performing essential work duties are provided appropriate clothing as available through the existing uniform clothing line.

 

G.       Lightning Warning

While lightning on the horizon should warn of potential danger, lightning associated with thunder, or thunder alone means there is immediate danger to individuals who are outdoors.  Lightning can strike 10 miles ahead of or behind the storm front, and thunderhead clouds.  Do not resume outdoor activities until 30 minutes after a storm passes.

 

H.        Eligibility for Emergency Leave

Any employee leave as a result of a weather emergency is administered under the provision of Policy 103.275 – “Eligibility for Paid Emergency Leave.”

 

I.         Current weather watches/warnings may be observed at the National Weather Service website:  http://www.weather.gov/.  Type in your zip code or click on the map to see current watches/warnings and radar images for your area.

 

REVIEW:      Annually

 

REFERENCES:         American Conference of Governmental Industrial Hygienists -TLVs and BEIs 

http://www.weather.gov/

http://www.crh.noaa.gov/pub/heat.htm

Policy 103.275 “Eligibility for Paid Emergency Leave”

 

SUPERSESSION:      Policy 105.126, “Adverse Weather Guideline,” 1/1/04.

All facility policies, memos, or other communications whether verbal, written, or transmitted by electronic means regarding this topic.

 

ATTACHMENTS:      None

 

/s/

Dennis L. Benson, Deputy Commissioner

Facility Services

 

Harley W. Nelson, Deputy Commissioner

Community and Support Services

 

Instructions

105.126SCL. “Adverse Weather Guideline”