comf (version 0.1.7)

calcIso7933: Calculating Heat Strain Indices based on ISO 7933

Description

calcIso7933 calculates Tre, SWtotg, Dlimtre, Dlimloss50 and Dlimloss95 based on ISO 7933. It additionally provides intermediate results from the calculation: Cres, Eres, Ep, SWp, Texp, Tskeq, Tsk, wp

Usage

calcIso7933(accl, posture, Ta, Pa, Tr, Va, Met, Icl, THETA, Walksp, Duration, 
weight, height, DRINK, Adu, spHeat, SWp, Tre, Tcr, Tsk, Tcreq, Work, imst, Ap, 
Fr, defspeed, defdir, HR, pb)

Arguments

accl

a numeric value presenting state of acclimation [100 if acclimatised subject, 0 otherwise]

posture

a numeric value presenting posture of person [sitting=1, standing=2, crouching=3]

Ta

a numeric value presenting air temperature in [degrees celsius]

Pa

a numeric value presenting partial water vapour pressure [kPa]

Tr

a numeric value presenting mean radiant temperature in [degrees celsius]

Va

a numeric value presenting air velocity in [m/s]

Met

a numeric value presenting metabolic rate in [W/(m*m)]

Icl

a numeric value presenting static thermal insulation of clothing [clo]

THETA

a numeric value presenting angle between walking direction and wind direction in [degrees]

Walksp

a numeric value presenting walking speed in [m/s]

Duration

a numeric value presenting the duration of the work sequence in [min]

weight

a numeric value presenting the body mass in [kg]

height

a numeric value presenting the body height in [m]

DRINK

a numeric value presenting if workers can drink as they want [1 if they can drink without restriction, 0 if restricted]

Adu

a numeric value presenting body surface area according to Du Bois [m*m]

spHeat

a numeric value presenting specific body heat [(W/(m*m))/K]

SWp

a numeric value presenting predicted sweat rate [W/(m*m)]

Tre

a numeric value presenting rectal temperature [degrees celsius]

Tcr

a numeric value presenting temperature of body core [degrees celsius]

Tsk

a numeric value presenting skin temperature at start [degrees celsius]

Tcreq

a numeric value presenting temperature of body core dependent on energy metabolism [degrees celsius]

Work

a numeric value presenting effective mechanical power [W/(m*m)]

imst

a numeric value presenting static moisture permeability index [-]

Ap

a numeric value presenting fraction of the body surface covered by the reflective clothing [-]

Fr

a numeric value presenting emissivity of the reflective clothing [-]

defspeed

a numeric value presenting if walking speed entered [1 if walking speed entered, 0 otherwise]

defdir

a numeric value presenting if walking direction entered [1 if walking direction entered, 0 otherwise]

HR

a numeric value presenting humidity ratio [g/kg]

pb

a numeric value presenting normal barometric pressure in [Pa]

Value

calcISO7933 returns a data.frame with the following items:

Tre

final rectal temperature [degrees Celsius]

SWtotg

total water loss [g]

Dlimtre

time when limit for rectal temperature is reached [min]

Dlimloss50

time when limit for water loss Dmax50 (7.5 percent of body mass of an average person) is reached [min]

Dlimloss95

time when limit for water loss Dmax95 (5 percent of body mass of 95 percent of the working people) is reached [min]

Cres

convective heat flow at respiration [W/(m*m)]

Eres

evaporative heat flow at respiration [W/(m*m)]

Ep

predicted evaporative heat flow [W/(m*m)]

SWp

predicted sweating rate [W/(m*m)]

Texp

temperature of the exhaled air [degrees Celsius]

Tskeq

skin Temperature in equilibrium [degrees Celsius]

Tsk

skin Temperature at the minute [degrees Celsius]

wp

predicted skin wettedness [-]

Details

All variables must have the same length 1.

References

Ergonomics of the thermal environment - Analytical determination and interpretation of heat stress using calculation of the predicted heat strain (ISO 7933:2004) Malchaire J., Piette A., Kampmann B., Mehnert P., Gebhardt H. J., Havenith G., Den Hartog E., Holmer I., Parsons K., Alfano G., Griefahn B. (2000), Development and validation of the predicted heat strain model, The Annals of Occupational Hygiene The Annals of Occupational Hygene, 45, pp 123-135 Malchaire J., Kampmann B., Havenith G., Mehnert P., Gebhardt H. J. (2000), Criteria for estimating acceptable exposure times in hot work environment, a review, International Archives of Occupational and Environmental Health, 73(4), pp. 215-220.

Examples

# NOT RUN {
## Calculation of a single set of values.
calcIso7933(accl = 100, posture = 2, Ta = 35, Pa = 4, Tr = 35, Va = 0.3, Met = 150, 
Icl = 0.5, THETA = 0, Walksp = 0, Duration = 480)

calcIso7933(100,2,35,4,35,0.3,150,0.5,0,0,480)
## Using several rows of data:
accl <- 100
posture <- 2
Ta <- c(40,35)
Pa <- c(2.5,4)
Tr <- c(40,35)
Va <- 0.3
Met <- 150
Icl <- 0.5
THETA <- 0
Walksp <- 0
Duration <- 480
maxLength <- max(sapply(list(accl, posture, Ta, Pa, Tr, Va, Met, Icl, THETA, Walksp, 
Duration), length))

PHI <- sapply(seq(maxLength), function(x) {calcIso7933(accl, posture, Ta[x], Pa[x], 
Tr[x], Va, Met, Icl, THETA, Walksp, Duration) } ) 
# }