Treshold Value Limit

Pages: 4 (893 words) Published: June 18, 2013
Name: Jane Wang

1.

TLV- Threshold Limit Value:
The threshold limit value of a chemical substance is a level to which it is believed a worker can be exposed day after day for a working lifetime without adverse health effects.

PPM - Parts Per Million:
This is a way of expressing very dilute concentrations of substances. Just as per cent means out of a hundred, so parts per million or ppm means out of a million. Usually describes the concentration of something in water or soil. One ppm is equivalent to 1 milligram of something per liter of water (mg/l) or 1 milligram of something per kilogram soil (mg/kg). A mechanic in an automotive repair shop is exposed to the following carbon monoxide levels over an 8 hour shift. Calculation for TLV and PPM

TLV in mg/m^3 = (TLV in ppm) (gram molecular weight)/24.45
*24.45 is the molar volume of air in liters
gram molecular weight of CO = 28.0101 g/mol
PPM = x(%) = x(ppm) / 10000

* 2 hours @ 34 ppm
TLV in mg/m^3 = 38.95 mg/m^3
PPM = 0.0034%

* 5 hours @ 40ppm
TLV in mg/m^3 = 45.82 mg/m^3
PPM = 0.0040%
* 1 hour @ 20ppm
TLV in mg/m^3 = 22.91 mg / m^3
PPM = 00020%
Yes the worker is over-exposed during the duration of their 8 hour shift. The primary goal of hazard recognition is “to reduce incidents, accidents, injuries and property damage.

The primary concept of the hierarchy of hazard control is the source. where elimination is an option if a task it too dangerous.”

The specific hierarchy outlined are as follows
* Engineering Controls
* Personal Protective Equipment
Engineering Controls:
* Monitor CO Levels to ensure levels stay below TLV limits * stream line the hours so the exposure gets evenly distributed in different * provide proper and efficient ventilation to exhaust the CO in the work place. * Eliminate the source of CO with alternative methods.

* Work with HR to alternate shifts or hire more...