EMIA

Temperature Thresholds S3EMIA-113-ATT1

1.0 Work-Rest Schedule

The prevention of heat stress is best performed through Supervisor observation of Employees and routine heat stress awareness training activities. However, it is also necessary to implement a work routine that incorporates adequate rest periods to allow Employees to remove protective clothing, drink fluids (vital when extreme sweating is occurring), rest and recover. The frequency and length of work breaks shall be determined by the Supervisor based upon the ambient , amount of sunshine, , the amount of physical labor being performed, the physical condition of the Employees (e.g., acclimated/not), and protective clothing being used.

1.1 Establishing a Work-Rest Schedule: 1.1.1 AECOM permits the use of either of two techniques to initially determine an appropriate daily work- rest schedule. These methods are:  Wet Bulb Globe Thermometer (WBGT) Method: This method is preferred if a WBGT meter is available.  Adjusted Temperature Method: This method should be used only if WBGT data is not available. 1.1.2 Either procedure will provide the Supervisor with a recommended routine; however, adjustments to this routine may be required to accommodate the specific daily conditions at the work site. 1.2 WBGT Work-Rest Schedule Guidelines: 1.2.1 If the measured WBGT is less than the action limit value, there is little risk of excessive exposure to heat stress, and work can continue.  Continue to monitor ambient conditions with the WBGT. However, if there are reports of the symptoms of heat-related disorders, then the analysis of little risk should be reconsidered.  If the measured WBGT is greater than the values in the following two tables, institute heat stress controls, including the associated work-rest cycle, and perform physiological monitoring as described in S3EMIA-113-PR1 Heat Stress.  Because of the physiological strain associated with very heavy work among less fit workers regardless of WBGT, values are not provided in Table 1 or 2 for continuous work or 75% work – 25% rest regimen. Physiological monitoring should always be implemented under these conditions. 1.2.2 Table 1, the Non-CPC Activities WBGT Chart, is intended for use where personnel are not utilizing Chemical Protective Clothing (CPC). Where workers are required to utilize CPC, Table 2, the CPC Activities WBGT Chart, will be used. 1.2.3 WBGT readings are compared directly with the values of the applicable WBGT Chart for the applicable work rate (where light work corresponds to minimal physical activity besides standing/watching; very heavy work corresponds to significant, continuous physical labor) to determine the work-rest frequency. Table 1. Non-CPC Activities WBGT Chart WBGT Work-Rest Regimen Light Work Moderate Work Heavy Work Very Heavy Work Continuous Work 85F (29.4C) 81F (27.2C) 78F (25.6C) 75% Work – 25% Rest 86F (30C) 83F (28.3C) 81F (27.2C) 50% Work – 50% Rest 88F (31.1C) 85F (29.4C) 83F (28.3C) 81F (27.2C) 25% Work – 75% Rest 90F (32.2C) 87F (30.6C) 86F (30C) 85F (29.4C)

Modified from ACGIH’s 2014 Threshold Limit Values for Chemical Substances and Physical Agents, for acclimatized workers.

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Table 2. CPC Activities WBGT Chart

WBGT Work-Rest Regimen Light Work Moderate Work Heavy Work Very Heavy Work Continuous Work 74F (23.3C) 70F (21.1C) 67F (19.4C)

75% Work – 25% Rest 75F (23.9C) 72F (22.2C) 70F (21.1C)

50% Work – 50% Rest 77F (25C) 74F (23.3C) 72F (22.2C) 70F (21.1C)

25% Work – 75% Rest 79F (26.1C) 76F (24.4C) 75F (23.9C) 74F (23.3C)

Modified from ACGIH’s 2014 Threshold Limit Values for Chemical Substances and Physical Agents, for acclimatized workers.

1.3 Humidex Based Work-Rest Schedule Guidelines 1.3.1 The Humidex method is a simplified way of protecting workers from heat stress. It is an equivalent scale intended to express the combined effects of warm and humidity. Humidex is used as a measure of perceived heat that results from the combined effect of excessive humidity and high temperature. 1.3.2 This method requires only a local air temperature and relative humidity value. Monitoring shall continue throughout the day for changing conditions. Identify a representative location where measurements can be taken. Measurements should be recorded at least hourly when ambient temperatures and 90°F (32°C) for personnel wearing normal permeable work clothes.  Step 1: On the Humidex table below, look up the temperature on the left (Celsius is located below RH>) and the relative humidity (RH) on the top. Determine the Humidex value.

F RH> 100% 95% 90% 85% 80% 75% 70% 65% 60% 55% 50% 45% 40% 35% 30% 25% 20% 108 42 55 52 50 48 46 106 41 55 53 51 48 46 44 104 40 55 53 51 49 47 45 43 102 39 55 53 51 49 47 45 43 41 100 38 Step 1 - Determine HUMIDEX VALUE 54 53 51 49 47 45 43 42 40 99 37 54 52 51 49 47 45 44 42 40 38 97 36 57 55 53 52 50 49 47 45 44 42 40 39 37 95 35 56 54 53 51 50 48 47 45 43 42 40 39 37 36 93 34 56 55 53 52 51 49 48 46 45 43 42 40 39 37 36 34 91 33 55 54 53 51 50 48 47 46 44 43 41 40 39 37 36 34 33 90 32 53 51 50 49 48 46 45 44 42 41 40 38 37 36 34 33 32 88 31 50 49 48 47 45 44 43 42 40 39 38 37 35 34 33 32 30 86 30 48 47 46 44 43 42 41 40 39 37 36 35 34 33 31 30 29 84 29 46 45 43 42 41 40 39 38 37 36 35 33 32 31 30 29 28 82 28 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 81 27 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 79 26 39 38 37 36 35 34 33 33 32 31 30 29 28 27 26 25 24 77 25 37 36 35 34 33 33 32 31 30 29 28 27 26 26 25 24 23

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 Step 2: Place the Humidex value into the Adjustment Table below. Determine the applicable adjustments based on the given work or task.

Heat Index Adjustment Table Step 2 - Risk Factor Adjustment Write in value What is the HUMIDEX value from the table in Step 1? Radiant Heat Adjustment Working in full-sun Add 2 Working in ½ or partial sun or weak radiant heat source Add 1 Working near very hot equipment surfaces or processes Add 2 Clothing: Pick One Only Short/long sleeve shirt and pants – no overalls None Overalls (e.g., Nomex suit) Add 3 Double layer overalls Add 5 Stop Impermeable clothing Perform Physiological Monitoring Acclimatization Have been working at least 5 of last 7 days in heat stress conditions. Subtract 4 Work Load & Miscellaneous Factors Light Work (Standing, slow walking) Subtract 2 Medium Work (Walking about with moderate lifting or pushing) None Heavy Work (Shoveling dry sand, carrying 50 lbs) Add 2 Very Heavy Work (Shoveling wet sand) Add 3 TOTAL – Compare to Heat Index Response Plan

 Step 3: Compare adjusted Heat Index Total to the Heat Index Response Plan table to obtain guidance for work/rest.

Heat Index Response Plan*

TOTAL Final Step 3 - HEAT INDEX Response NUMBER 30-33 alert & information & water 34-37 warning & increase water 38-39 75% work - 25% rest & monitor for signs of heat stress 40-41 50% work - 50% rest & monitor for signs of heat stress 42-44 25% work - 75% rest & monitor for signs of heat stress 45+ Perform Physiological Monitoring

* Percent work and rest/recovery are on a per hour basis. Adjustments and subsequent work/rest cycle recommendations are rough guidelines only. No heat stress prediction scheme can replace monitoring of symptoms or a health care practitioners advice in the case of individuals with special medical conditions or predisposing circumstances for heat related illness. Always pay attention to the way workers are feeling. Recuperate if fatigued, nauseated, dizzy or thirsty,

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1.4 Adjusted Temperature Work-Rest Schedule Guidelines: This method can be utilized where WBGT data is not available, and requires only that the ambient temperature be known. Adjustment factors are applied to the ambient temperature to account for departures from ideal conditions (sunny conditions, light , moderate humidity and a fully acclimated work force). The adjustments will be made by addition or subtraction to the ambient temperature reading, or changes in table position, as indicated in Table 3. Adjustments are independent and cumulative, all applicable adjustments should be applied. The result is the Adjusted Temperature, which can be compared with the values in Table 4 for the applicable work rate (where light work corresponds to minimal physical activity besides standing/watching; very heavy work corresponds to significant, continuous physical labor) to determine the work-rest schedule. Table 3. Temperature Adjustment Factors Time of Day Before daily temperature peak1 +2F (+1.11C) 10 am – 2 pm (peak sunshine) +2F (+1.11C) Sunshine No +1F (+0.56C) Partly Cloudy (3/8 – 5/8 cover) -3F (-1.67C) Mostly Cloudy (5/8 – 7/8 cloud cover) -5F (-2.78C) Cloudy (>7/8 cloud cover) -7F (-3.89C) Indoor or nighttime work -7F (-3.89C) (ignore if indoors or wearing CPC) Gusts greater than 5 miles per hour at least once per minute -1F (-0.56C) Gusts greater than 10 miles per hour at least once per minute +2F (+1.11C) Sustained greater than 5 miles per hour -3F (-1.67C) Sustained greater than 10 miles per hour -5F (-2.78C) Humidity (ignore if wearing CPC) Relative Humidity greater than 90% +5F (+2.78C) Relative Humidity greater than 80% +2F (+1.11C) Relative Humidity less than 50% -4F (-2.23C) Chemical Protective Clothing (CPC) Modified Level D (coveralls, no respirator) +5F (+2.78C) Level C (coveralls w/o hood, full-face respirator) +8F (+4.45C) Level C (coveralls with hood, full-face respirator) +10F (+5C) Level B with airline system (hooded chemical resistant clothing) +9F (+5.56C) Level B with SCBA (hooded chemical resistant clothing) +9F (+5.56C) and right one column2 Level A (totally encapsulating chemical protective suit) +14F (+7.78C) and right one column Other Specified in the HASP Miscellaneous Unacclimated work force +5F (+2.78C) Partially acclimated work force +2F (+1.11C) Working in shade -3F (-1.67C) Breaks taken in air conditioned space -3F (-1.67C)

For complete descriptions of Level A through D Protective Clothing refer to Unites States 29 CFR 1910.120 Appendix B

1 This adjustment accounts for temperature rise during the day. If the temperature has already reached its daytime peak it can be ignored. 2 Locate the proper column based on work rate, then move one column to the right (next higher work rate) before locating the corresponding adjusted temperature.

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Table 4. Work-Rest Schedule Based on Adjusted Temperature

Adjusted Temperature Work-Rest Regimen Light Work Moderate Work Heavy Work Very Heavy Work

No specified < 80F < 75 < 70 < 65 requirements (22.67C) (23.88C) (21.11C) (18.33C) 15 minute break 80F – 90F 75 – 85 70 – 80 65 – 75 every 90 minutes of (22.67C) - (32.22C) (23.88C) - (29.44C) (21.11C) - (22.67C) (37.77C) - (23.88C) work 15 minute break >90 – 100 > 85 – 95 >80 – 85 >75 – 80 every 60 minutes of (32.22C) - (37.77C) (23.88C) - (35C) (22.67C) - (23.88C) (23.88C) - (22.67C) work 15 minute break >100 – 110 >95 – 100 >85 – 90 >80 – 85 every 45 minutes of (37.77C) - (43.33C) (35C) - (37.77C) (23.88C) - (32.22C) (22.67C) - (23.88C) work 15 minute break >110 – 115 >100 – 105 >90 – 95 >85 – 90 every 30 minutes of (43.33C) - (46.11C) (37.77C) – (40.55C) (32.22C) - (35C) (23.88C) - (32.22C) work 15 minute break >115 – 120 >105 – 110 >95 -100 >90 – 95 every 15 minutes of (46.11C) - (48.88C) (40.55C) - (43.33C) (35C) - (37.77C) (32.22C) - (35C) work

>120 >110 >100 >95 Stop Work (48.88C) (43.33C) (37.77C) (35C)

Note: Time spent performing decontamination or donning/doffing CPC should not be included in calculating work or break time lengths.

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