Mr Bakini Mohd Nor - Sbmn Synergy
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Transcript of Mr Bakini Mohd Nor - Sbmn Synergy
OH&ES TRAINING CENTREOH&ES TRAINING CENTREOH&ES TRAINING CENTREOH&ES TRAINING CENTRE
SBMN SYNERGY SDN BHD(PSMB Training Provider Reg. No #1191)
7426, JALAN KUBANG KURUS, 24000 CUKAI, KEMAMAN,
TERENGGANU.
TEL : 09-8502490 / 91, 8597081
FAX : 09-8595324 / 8596819
EMAIL : [email protected]
SBMN SYNERGY SDN BHD
BAKINI MHD NOR MIM-CPT
3M COMPETENT TRAINER SINCE 1997
TRAINER ID # 01
RESPIRATORY PROTECTION PROGRAM TRAINED BY:
- 3M MALAYSIA SDN BHD
- 3M OH&ES DIVISION, USA
- COEH UNIVERSITY OF CALIFORNIA AT BERKELEY, USA
- AMERICAN INDUSTRIAL HYGIENE ASSOCIATION (AIHA), USA- AMERICAN INDUSTRIAL HYGIENE ASSOCIATION (AIHA), USA
- MALAYSIAN INDUSTRIAL HYGIENE ASSOCIATION (MIHA)
PROFESSIONAL MEMBERSHIPS:
- MEMBER OF NIOSH MALAYSIA
- FULL MEMBER OF MALAYSIAN INDUSTRIAL HYGIENE
ASSOCIATION (MIHA)
- INTERNATIONAL SOCIETY FOR RESPIRATORY PROTECTION (ISRP),
AMERICAS SECTION
- MEMBER OF AMERICAN CONFERENCE OF GOVERNMENTAL
INDUSTRIAL HYGIENISTS (ACGIH)
- AMERICAN INDUSTRIAL HYGIENE ASSOCIATION (AIHA), USA
DETERMINING COMPLIANCE WITH PERMISSIBIE DETERMINING COMPLIANCE WITH PERMISSIBIE
EXPOSURE LIMIT USING RESPIRATOR FOR NORMAL EXPOSURE LIMIT USING RESPIRATOR FOR NORMAL
WORKSHIFT AND EXTENDED WORKSHIFTWORKSHIFT AND EXTENDED WORKSHIFT
Objectives:
� Ensure worker’s exposure to any substance is kept as low as reasonably
practicable and does not exceed the substance's PEL.practicable and does not exceed the substance's PEL.
� Determine the daily time-weighted exposure during the period when the
respirator is worn and not worn.
� Taking into account the Assigned Protection Factor (APF) – the main
determinant factor that decides which respirator to be selected and Total Inward
Facial Leakage (TIL), when calculating the daily time-weighted exposure during
the period when the respirator is worn and not worn.
� Apply the Brief and Scala Model - most conservative estimate, when
adjusting the Permissible Exposure Limit (PEL) for working with extended workshift.
Daily time-weighted exposure =
for periods during respirator
is worn and not worn (dose)
is based on fundamental principles prescribed by :-
Compliance with permissible exposure limit using respirator
(Cw tw + Cnwtnw + Cniltnw )
8-hour
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE
LIMIT USING RESPIRATOR FOR NORMAL WORKSHIFT LIMIT USING RESPIRATOR FOR NORMAL WORKSHIFT
Compliance with permissible exposure limit using respirator
USECHH Regulations 2000: Regulation 8
(1) For the purpose of determining whether the employer has complied within
the permissible exposure limit, the degree of protection afforded by the
respirator for the periods during which the respirator is worn shall be taken
into account
(2) The period referred to in subregulation (1) shall be averaged with the
exposure level of the airborne concentration during the period when
respirators are not worn to determine the employee’s daily time-weighted
average exposure.
Compliance with permissible exposure limit using respirator
By applying the formula :
Daily time-weighted exposure =
for periods during respirator
is worn and not worn (Dose)
(Cw tw + Cnwtnw + Cniltnw )
8-hour
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR NORMAL WORKSHIFT USING RESPIRATOR FOR NORMAL WORKSHIFT
is worn and not worn (Dose)
Where Cw tw = exposure concentration, duration while wearing respirator
Cnwtnw = exposure concentration, duration while not wearing respirator
Cniltnw = no exposure concentration or zero exposure
TWA = C1T1 + C2T2 + EE..+ CnTn(Dose)
Total Time ( 8-hour)
(Cw tw + Cnwtnw + Cniltnw )
8-hour
is based on
Compliance with permissible exposure limit using respirator
Example
Exposure : 350 ppm of Xylene
for 8-hr period
Don / Wear : Half facepiece respirator
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR NORMAL WORKSHIFT USING RESPIRATOR FOR NORMAL WORKSHIFT
Don / Wear : Half facepiece respirator
Type: Air Purifying Respirator (APR)
Note : (APF = 10, Total Inward Facial Leakage : 10%)
a. Time duration doning/ wearing 5 hours
3M 6000 series half facepiece respirator
b. Time duration not doning/ wearing 1 hour
3M 6000 series half facepiece respirator
c. Time duration not doning/ wearing 2 hours
3M 6000 series half facepiece respirator
when do not expose to xylene (Lunch ,safety briefing and prayers time)
Compliance with permissible exposure limit using respirator
By applying the formula :
Daily time-weighted exposure = (Cw tw + Cnwtnw + Cniltnw )
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR NORMAL WORKSHIFT USING RESPIRATOR FOR NORMAL WORKSHIFT
Daily time-weighted exposure =
for periods during respirator
is worn and not worn (Dose)
Step 1 :-
Cw tw = exposure concentration, duration while wearing respirator
= 35 ppm x 5 hours
= 175 ppm
(Cw tw + Cnwtnw + Cniltnw )
8-hour
Compliance with permissible exposure limit using respirator
Explaination:
Inhalation of exposure = Total Inward Facial Leakage x Exposure
for Xylene when respirator = 10% x 350 ppm
Is worn = 35 ppm of Xylene
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR NORMAL WORKSHIFT USING RESPIRATOR FOR NORMAL WORKSHIFT
Is worn = 35 ppm of Xylene
Types of RespiratorTotal Inward
Facial
Leakage
APF = Co
Ci
= 100%
10%
Half Facepiece (Air
Purifying Respirator)
10% 10
Note:-
Total Inward Facial Leakage of 10% is the maximum leakage for a given type of
respirator allowed by NIOSH,USA. APF is also known as Degree of Protection.
USECHH Regulations 2000: Regulation 8 states that:
(3) For the purpose of this regulation, “degree of protection” means the ratio
of the airborne concentration of the contaminant outside the respirator to the
concentration of the contaminant inside the facepiece of the respirator.
Airborne Concentration of the Workplace Exposure
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR NORMAL WORKSHIFT USING RESPIRATOR FOR NORMAL WORKSHIFT
Airborne Concentration of the
Contaminants Outside the Respirator
= =
Concentration of the Contaminant
Inside the Respirator Facepiece
Degree of
Protection
Degree of Protection = Assigned Protection Factor ( APF )
Total Inward
Leakage (TIL) or
Exposure Limit
=
Workplace Exposure
Concentration
“The effectiveness (degree of protection) of a respirator determined by its protection factor
(PR). In the selection of respirators, the assigned protection factors are used.”
- “Guidelines on the use of Personal Protective Equipment Against
Chemicals Hazards” 2005. ( Page 11 )
*Workplace Exposure Concentration
Total Inward Leakage (TIL) or
Exposure Limit
APF needed =
ASSIGNED PROTECTION FACTOR (APF)ASSIGNED PROTECTION FACTOR (APF)
By adopting the Right APF, the leakage or Total Inward Leakage
(TIL) can be reduced below the Exposure Limit
* “Employers must identify and evaluate the respiratory hazard(s) in the workplace. This
evaluation must include a reasonable estimate of employee exposures to respiratory
hazard (s) and an identification of the contaminant’s chemical state and physical form”
- “Guidelines On the Use of Personal Protective Equipment Against
Chemicals Hazards” 2005. (Page 24)
* 8-hr TWA or exposure within 15-minute TWA
Step 2 :-
Cnwtnw = exposure concentration, duration while not wearing respirator
Exposure : 350 ppm of Xylene
without wearing respirator (100% exposure)
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR NORMAL WORKSHIFT USING RESPIRATOR FOR NORMAL WORKSHIFT
= (350 ppm x 1 hour)
= 350 ppm
Step 3 :-
Cniltnw = rest period without exposure and not wearing respirator
= zero exposure x 2 hours
= 0 ppm
Step 4 :-
Total (Cw tw + Cnwtnw + Cniltnw ) divide by 8-hour (duration of exposure)
= 175 ppm + 350 ppm + 0 ppm
8-hour
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR NORMAL WORKSHIFT USING RESPIRATOR FOR NORMAL WORKSHIFT
8-hour
= 66 ppm of Xylene (Dose)
66 ppm of Xylene is below the PEL of Xylene which is
100 ppm. This is in compliance with the PEL Limits Using
Respirators USECHH Regulations 2000 : Regulation 8.
Able to avoid occupational diseases.
The validity of this calculation for the daily time-weighted exposure
will be based on the following considerations :-
1. The Respiratory Protective Equipment (RPE) must be approved by Director
General of DOSH and tested according to international recognized standards
such as ANSI, NIOSH (USA), AS,NZS, JIS and others.
2. Respirator selected must be based on
Assigned Protection Factor (APF) > Hazard Ratio
for the selected respirator Exposure 8-hr TWA
PEL
Continued(..
[ ]
*Workplace Exposure Concentration
Total Inward Leakage (TIL)
APF needed =Total Inward Leakage (TIL)
By adopting the Right APF, the leakage or Total Inward Leakage
(TIL) can be reduced below the Exposure Limit
* “Employers must identify and evaluate the respiratory hazard(s) in the workplace. This
evaluation must include a reasonable estimate of employee exposures to respiratory
hazard (s) and an identification of the contaminant’s chemical state and physical form”
- “Guidelines On the Use of Personal Protective Equipment Against
Chemicals Hazards” 2005. (Page 24)
* 8-hr TWA or exposure within 15-minute TWA
3. Respirator facepiece and equipment must be free from defects to avoid
malfunction of the respirator.
Continued(..
4. Correct selection of filtering media for negative air purifiying respirator.
Continued(..
Beware!!!
The use of incorrect cartridge or
incorrect filtering gives workers a false
sense of security and in addition may
cause occupational diseases.
5. Respirator user must passed the Qualitative Fit-Test or Quantitative Fit-Test
conducted by competent person trained by respirator manufacturer. Respirator
Fit Test must be conducted at least once a year recommended by most
respirator manufacturers.
Continued(..
6. Respirator User Seal Check (Fit Check) must be performed after donning the
respirator facepiece.
Continued(..
The main objective of User Seal Check is to ensure proper fitting of tight fitting
facepiece and minimize respirator faceseal leakages.
7. Prior doning, ensure that respirator user must be free from facial hair such as
stubble, moustache, beard, and long side burns, that might affect the sealing
surface of the respirator. Respirator user must also ensure that other PPE such
as Goggle, Safety Spectacles , or other PPE should not interfere with the face-
to-facepiece seal or valve function.
Continued(..
8. Appropriate chemical protective clothing including glove and other relevant PPE
must be don when chemical can be absorbed through skin.
Continued(..
Chemical
Resistant glove
Chemical Protective
Clothing
Chemical
Resistant Boot
Respirator
9. RPE must be thoroughly clean, kept store so that contaminated it free from
chemical contamination.
Continued(..
Compliance with permissible exposure limit using respirator
Example
Exposure : 350 ppm of Xylene
Don / Wear : Half facepiece respirator
Type: Air Purifying Respirator (APR)
Note : (APF = 10, Total Inward Facial Leakage : 10%)
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFTUSING RESPIRATOR FOR EXTENDED WORKSHIFT
Note : (APF = 10, Total Inward Facial Leakage : 10%)
No. of hours worked : 12 hours per shift
a. Time duration doning/ wearing 9 hours
3M 6000 series half facepiece respirator
b. Time duration not doning/ wearing 1 hour
3M 6000 series half facepiece respirator
c. Time duration not doning/ wearing 2 hours
3M 6000 series half facepiece respirator
when do not expose to Xylene (Lunch ,safety briefing and prayers time)
Compliance with permissible exposure limit using respirator
By applying the formula :
Daily time-weighted exposure = (Cw tw + Cnwtnw + Cniltnw )
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFTUSING RESPIRATOR FOR EXTENDED WORKSHIFT
Daily time-weighted exposure =
for periods during respirator
is worn and not worn (Dose)
Step 1 :-
Cw tw = exposure concentration, duration while wearing respirator
= 35 ppm x 9 hours
= 315 ppm
(Cw tw + Cnwtnw + Cniltnw )
12-hour
Compliance with permissible exposure limit using respirator
Explaination:
Inhalation of exposure = Total Inward Facial Leakage x Exposure
for Xylene when respirator = 10% x 350 ppm
Is worn = 35 ppm of Xylene
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFTUSING RESPIRATOR FOR EXTENDED WORKSHIFT
Is worn = 35 ppm of Xylene
Types of RespiratorTotal Inward
Facial
Leakage
APF = Co
Ci
= 100%
10%
Half Facepiece (Air
Purifying Respirator)
10% 10
Note:-
Total Inward Facial Leakage of 10% is the maximum leakage for a given type of
respirator allowed by NIOSH,USA. APF is also known as Degree of Protection.
Step 2 :-
Cnwtnw = exposure concentration, duration while not wearing respirator
Exposure : 350 ppm of Xylene
without wearing respirator (100% exposure)
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFTUSING RESPIRATOR FOR EXTENDED WORKSHIFT
= (350 ppm x 1 hour)
= 350 ppm
Step 3 :-
Cniltnw = rest period without exposure and not wearing respirator
= zero exposure x 2 hours
= 0 ppm
Step 4 :-
Total (Cw tw + Cnwtnw + Cniltnw ) divide by 12-hour (duration of exposure)
= 315 ppm + 350 ppm + 0 ppm
12-hour
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFT USING RESPIRATOR FOR EXTENDED WORKSHIFT
12-hour
= 55 ppm of Xylene (Dose)
The normal PEL for Xylene 100 ppm is no longer valid for
extended workshift. Need to be adjusted using Brief and Scala
model.
Selected Model : Brief and Scala
Brief and Scala model is the simplest and most
conservative model. “Conservative” means results in the
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFTUSING RESPIRATOR FOR EXTENDED WORKSHIFT
conservative model. “Conservative” means results in the
greatest reduction of the exposure limit.
Brief and Scala compensates for unusual work
schedules by reducing the permissible concentration in
proportion to both the increase in exposure time and the
reduction in recovery time.
BRIEF AND SCALA MODEL
This model, originally derived within the petroleum industry, reduces the 8-hour
OEL/PEL proportionally for both increased exposure and reduced recovery time.
The suggested approach is set out below.
Daily Adjustments of Occupational Exposure Limits :
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFTUSING RESPIRATOR FOR EXTENDED WORKSHIFT
Daily Adjustments of Occupational Exposure Limits :
Daily Reduction Factor = { ( )}
Where h = hours worked per day
Adjusted Exposure Limit = 8 hr TLV/PEL/OEL x Daily Reduction Factor
{ ( )}
8 x
h
24 – h
16
8
h24 – h
16
ADJUSTMENT OF TLV/PEL/OEL FOR EXTENDED WORKSHIFT
USING BRIEF AND SCALA MODEL
EXTENDED WORKSHIFT
Work Duration ( h )
(Hours Worked Per Day)
Daily Reduction Factor
10 hours 0.7
12 hours 0.512 hours 0.5
Adjusted PEL = PEL x Daily Reduction Factor
Explaination on Derivation of Reduction Factor
A) Extended workshift = 10 hours worked per day
Reduction Factor = (8/10) x (24 – 10) / 16)
= 0.7 (Reduction Factor)
B) Extended Workshift = 12 hours worked per day
Reduction Factor = (8/12) x (24 – 12) / 16)
= 0.5 (Reduction Factor)
ADJUSTMENT OF TLV/PEL/OEL FOR EXTENDED WORKSHIFT
USING BRIEF AND SCALA MODEL
Work Duration ( h )10 hours 12 hours
Chemical Exposed : Xylene
TLV / PEL / OEL : 100 ppm
Formula for Brief & Scala : 8 x (24-h) x PEL
16 x h
Work Duration ( h )
(Hours Worked Per Day)10 hours 12 hours
Rest Period
(Recovery Time)14 hours 12 hours
Daily Reduction Factor 0.7 0.5
Adjusted TLV/PEL/OEL
( ppm )70 ppm 50 ppm
Note :-
•↑Work Duration ↓ Recovery Time ↓ Adjusted TLV/PEL/OEL
•Brief and Scala Model is the most conservative estimate.
BRIEF AND SCALA MODEL
Adjusted Exposure Limit = 8 x (24 – h) x PEL
for Xylene for 12 hours 16 x h
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFTUSING RESPIRATOR FOR EXTENDED WORKSHIFT
for Xylene for 12 hours 16 x h
exposure
= 8 x (24 – 12) x 100 ppm
16 x 12
= 50 ppm
where h = hours worked per day
55 ppm is the Daily Time-Weighted > 50 ppm adjust PEL for Xylene using
Average for 12 hours exposure Brief & Scale Model for 12 hours work
period.
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFT USING RESPIRATOR FOR EXTENDED WORKSHIFT
When Daily TWA for 12-hr exposure exceeded the adjusted PEL, Xylene may
be elevated in the blood which may lead to occupational disease.
Recommendations :-
First recommendation
Select respirator with next higher APF which Full Facepiece (APR) with APF of 50.
APF = *50
* Assigned Protection Factors for the Revised Respiratory
Protection Standard ; Occupational Safety and Health
Administration U.S. Department of Labor ; OSHA 3352-02,
2009
Compliance with permissible exposure limit using respirator
Example
Exposure : 350 ppm of Xylene
for 12-hr period
Don / Wear : Full facepiece respirator
Type: Air Purifying Respirator (APR)
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFTUSING RESPIRATOR FOR EXTENDED WORKSHIFT
Type: Air Purifying Respirator (APR)
Note : (APF = 50, Total Inward Facial Leakage : 2%)
No. of hours worked : 12 hours per shift
a. Time duration doning/ wearing 9 hours
3M 6000 series half facepiece respirator
b. Time duration not doning/ wearing 1 hour
3M 6000 series half facepiece respirator
c. Time duration not doning/ wearing 2 hours
3M 6000 series half facepiece respirator
when do not expose to xylene (Lunch ,safety briefing and prayers time)
Compliance with permissible exposure limit using respirator
By applying the formula :
Daily time-weighted exposure = (Cw tw + Cnwtnw + Cniltnw )
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFTUSING RESPIRATOR FOR EXTENDED WORKSHIFT
Daily time-weighted exposure =
for periods during respirator
is worn and not worn (Dose)
Step 1 :-
Cw tw = exposure concentration, duration while wearing respirator
= 7 ppm x 9 hours
= 63 ppm
(Cw tw + Cnwtnw + Cniltnw )
12-hour
Compliance with permissible exposure limit using respirator
Explaination:
Inhalation of exposure = Total Inward Facial Leakage x Exposure
for Xylene when respirator = 2% x 350 ppm
Is worn = 7 ppm of Xylene
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFTUSING RESPIRATOR FOR EXTENDED WORKSHIFT
Types of RespiratorTotal Inward
Facial Leakage
APF = Co
Ci
= 100%
2%
Half Facepiece (Air
Purifying Respirator)
2% *50
Note:-
Total Inward Facial Leakage of 2% is the maximum leakage for a given type of respirator
allowed by NIOSH,USA. APF is also known as Degree of Protection.
* Assigned Protection Factors for the Revised Respiratory Protection Standard ; Occupational Safety and
Health Administration U.S. Department of Labor ; OSHA 3352-02, 2009
Step 2 :-
Cnwtnw = exposure concentration, duration while not wearing respirator
Exposure without wearing respirator (100% exposure)
: 350 ppm of Xylene
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFTUSING RESPIRATOR FOR EXTENDED WORKSHIFT
= (350 ppm x 1 hour)
= 350 ppm
Step 3 :-
Cniltnw = rest period without exposure and not wearing respirator
= zero exposure x 2 hours
= 0 ppm
Step 4 :-
Total (Cw tw + Cnwtnw + Cniltnw ) divide by 12-hour (duration of exposure)
= 63 ppm + 350 ppm + 0 ppm
12-hour
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFT USING RESPIRATOR FOR EXTENDED WORKSHIFT
12-hour
= 34 ppm of Xylene (Dose)
The normal PEL for Xylene 100 ppm is no longer valid for
extended workshift.
34 ppm is the Daily Time-Weighted < 50 ppm adjusted PEL for Xylene using
Average 12 hours exposure Brief & Scala Model for 12 hours
using Full Facepiece (APR) work period.
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFT USING RESPIRATOR FOR EXTENDED WORKSHIFT
Occupational Disease can be avoided.Occupational Disease can be avoided.
Second recommendation:
Half Facepiece APF can be selected provided the duration of exposure is
reduced. Implement job rotation
LIMITATIONS ON BRIEF AND SCALE MODEL
� Not applicable to justify very high exposures for short
durations
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFTUSING RESPIRATOR FOR EXTENDED WORKSHIFT
durations
� Not appropriate for many of the metals and mineral
dust.
However, recommended standards for extended
workshift operation, please refer to :-
“Recommended Exposure Reduction Factors for
Western Australian Mining Industry”.
Reference :-
Department of Minerals and
Energy Western
Australia, Discussion Paper
: Unusual Workshift and
Occupational Exposure
Standards. J
Oostehorf, 1983. Document
No. ZME263AA.
LIMITATIONS ON BRIEF AND SCALE MODEL
Example
Exposure to silica dust for extended workshift for 192 hours per month.
Health effect of silica is Silicosis. Typical respiratory disease. Threshold
Limit Value for Silica is 0.025 mg/m3
DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT DETERMINING COMPLIANCE WITH PERMISSIBIE EXPOSURE LIMIT
USING RESPIRATOR FOR EXTENDED WORKSHIFTUSING RESPIRATOR FOR EXTENDED WORKSHIFT
Limit Value for Silica is 0.025 mg/m3
TLV Silica (R) Exposure Reduction Factor 170/x
TLV/BEI x for more than working hours
2011 ACGIH Booklet > 170 hours /month
0.025 mg/m3 x 170
[(R) means respirable] 192
= 0.022 mg/m3
Adjusted TLV for Silica Working hours = 0.022 mg/m3 of Silica
greater than 170 hours per month
Take Care and Good Luck