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ES&H Manual
Chapter 6670 Heat and Cold Stress Mitigation Program
Jefferson Lab defines heat and cold stress as the physical and physiological reactions of a worker to temperatures that fall outside the normal comfort zone. The potential for heat and cold stress at Jefferson Lab exists mainly during the summer and winter months.

Mitigation actions are used to reduce heat and cold stress hazard conditions. The actions defined within this section meet or exceed the contractual requirements of 10 CFR 851.

Jefferson Lab recognizes that the most effective mitigation technique for heat and cold stress conditions is to wear appropriate clothing, and personal protective equipment. Work planning at Jefferson Lab, particularly during the summer months, considers ambient temperature and implements mitigation techniques as required.

Jefferson Lab uses the National Weather Service Heat Stress Index for areas exposed to ambient conditions. For indoor temperature monitoring, application guidelines, and calculations, the 2005 Threshold Limit Values for Physical Agents in the Work Environment section on Thermal Stress - Heat Stress & Heat Strain[1] is used (measured as the Wet Bulb Globe Temperature (WBGT)).

This chapter does not address specific hazards or injuries resulting from sudden exposure to cryogenic materials. (See ES&H Manual Chapter 6550 Cryogenic Safety Program.)


T1 Heat Stress Work Cessation Procedure
Areas of known routine hot working environments for all or part of the year are monitored on a periodic basis. ES&H Manual Chapter 6670 Appendix T1 Heat Stress Work Cessation Procedure addresses the procedure used to monitor and mitigate potential injury or illness due to heat stress.
T2 Cold Stress Work Cessation Procedure
As of the approval date of this chapter, there are no known work environments with temperatures that would be considered cold stress areas. One area with routine cold conditions is the food refrigeration area of CEBAF Center. However, this area is not occupied for continuous work but only visited as needed. ES&H Manual Chapter 6670 Appendix T2 Cold Stress Work Cessation Procedure addresses the procedure used to mitigate potential injury or illness due to cold stress.

Management authority may be delegated at the discretion of the responsible manager.

Everyone at Jefferson Lab
Industrial Hygiene
  • Provide calibrated equipment and appropriate training for temperature monitoring for specialized measurements. This specialized monitoring uses calibrated instrumentation to determine the wet bulb globe temperature and decisions based on the 2005 Threshold Limit Values for Physical Agents in the Work Environment.
  • Advise management when cessation of work criteria is to be implemented.
  • Maintain heat and cold monitoring records in accordance with department procedures.
Facilities Management and Logistics
  • Maintain the on-site Jefferson Lab weather station and provide a link to the data on a Jefferson Lab web page (currently
  • Monitor Jefferson Lab's weather station data and send warning notifications to Supervisors/Subcontracting Officer's Technical Representatives/Sponsors, ESH&Q Professionals, and others upon request.
Supervisor/Subcontracting Officer's Technical Representative (SOTR)/Sponsor
  • Request assistance as needed from Industrial Hygiene when work assignments involve heat-stress conditions.
  • Minimize worker's exposure to heat sources when feasible.
    • Allow for acclimatization in work plan when elimination of heat stress conditions is not feasible.
  • Provide heat and cold stress hazard awareness to workers when appropriate. (See ES&H Manual Chapter 4100 Appendix T2 Informal Safety Awareness Training.) Guidance/talking points may be requested from Industrial Hygiene or Occupational Medicine.
  • Provide appropriate rest periods for workers. Consult Industrial Hygiene for appropriate work/rest schedules.
   SOTR also
  • Ensure subcontractor personnel abide by their Jefferson Lab accepted procedure or this procedure's requirements.
  • Inform subcontracted workers of heat and cold stress warnings and notifications.
  • Ensure subcontracted workers are properly advised of work modification and rest periods.
  • Ensure fluid replacement sources and shelter techniques are available.
  • Notify ESH&Q of heat and/or cold stress areas that may require monitoring.
  • Review and accept subcontractor's heat and cold (thermal) stress program which must meet or exceed the requirements of this Jefferson Lab program;

Document Control:
    APPROVAL DATE:   06/04/15
    REVIEW DATE:  06/04/18
    • Revision 1.3 - 06/04/15  Periodic Review; updated Industrial Hygiene responsibilities.
    • Revision 1.2 - 09/27/12  Periodic review. No changes required.
    • Revision 1.1 - 05/10/11  Updated to provide for "hot work" activities
    • Revision 1.0 - 05/09/09  Updated to reflect current laboratory operations.

[1] American Conference of Governmental Industrial Hygienists (ACGIH) 2005 Version
[2] Heat Stress Symptoms include: Headache, dizziness, lightheadedness or fainting; weakness and moist skin; mood changes such as irritability or confusion; upset stomach or vomiting.

This document is controlled as an on-line file. It may be printed but the print copy is not a controlled document. It is the user's responsibility to ensure that the document is the same revision as the current on line file. .