www.arbounie.nl

Exposure to solvents in the metal fabrication

and engineering industry

2nd European Conference on AWARE and other coding

systems, Gent, October 4 & 5, 2007

Henri Heussen, PhD, &

Hester Dekker, MSc

Background

1. Web based tool metal sector: coating & degreasing

2. Aim: exposure to solvents self risk assessment by SME’s and larger companies

Tool: two validated routes

Good Practices (Risk Management Measures = RMM) Model: Occupational Air Requirement (OAR) or Required Air Quantity

(RAQ)

This part: validation of good practices and applied ventilation modelNext part IVAM: using the same exposure data > validation of AWARE

ventilation model

Activities studied

Good Practices

Degreasing by dipping – (semi) closed system

Mixing paint – closed mixer

Cleaning spray guns – closed washing machine with LEV

Model

Brushing/rolling

Spraying

Model: calculation OAR

n

i i

iii

OEL

fVOAR

1

1000

Legenda:

OAR: Occupational Air Requirement (m3/l)

Vi: Volume solvent/liter paint (ml/l)

i: index including all solvents in the paint

ρi: specific gravity (g/ml)

fi: evaporation factor (default 1)

OELi: Occupational Exposure Limit solvent (mg/m3)

or hardener & thinner

or hardener & thinner

Calulation needed ventilation

QOAR: Ventilation needed according to OAR (m3/hr)

OAR: Occupational Air Requirement (m3/l)

Ve: Amount used (l)

T: Time (hr)

T

VeOARQOAR

Calculation Exposure Index (EI)

Legenda:

EImodel: Exposure index

QOAR: Needed ventilation (m3/hr)

Qd: Actual ventilation (m3/hr)

d

OARmodel Q

QEI

Results - Good Practice mixing paint:

closed mixer10 comp.32 meas.

EI

RMM

Conclusions Good Practices:

Predefined Good Practices are indeed good (statistically validated)

Also other Good Practices found (some statistically validated)

Detailed description of Good Practice is necessary and a prerequisite for correct use of the tool

Results brushing/rolling(excluding natural ventilation) 7 companies

20 measurem.

y = 0,66x + 0,12R2 = 0,71

0,0

1,0

2,0

3,0

4,0

0,0 1,0 2,0 3,0 4,0

BI gemeten

BI

mo

delE

I mo

del

EI measurements

Results spraying(excluding natural ventilation) 6 companies

14 measurem.

y = 0,98x + 0,36R2 = 0,88

0,0

1,0

2,0

3,0

4,0

5,0

6,0

7,0

8,0

0,0 1,0 2,0 3,0 4,0 5,0 6,0 7,0 8,0

BI gemeten

BI

mo

delE

I mo

del

EI measurements

Conclusions model

Very good correlation between model and measurement data

However, model does not always overestimate

Therefore for brushing/rolling a safety factor is needed!

For spraying not a priori necessary > political decision

To be calculated on the basis of sensitivity/specificity

Conclusions model (continued)

After adding safey factor(s) model = validated exposure

assessment tool

Erring to the side of caution: separation between local and general ventilation MSDS upper limit range (volume solvent/l) more than one sprayer in the same room > total amount of

solvents used by all sprayers attributed to one sprayer

Covers a wide range: in amount of paint used per time room volume type of ventilation ventilation capacity measured exposure index

Thanks for your attention!

This study:

- performed by order of the social partners (FME-CWM, Metaalunie,

FNV, CNV, De Unie)

- supported by the Ministry of SZW (VASt programme)