Health and safety in the prep lab: a step-by-step guide to installing an efficient and cost effective dust

collecting and ventilation system

Heather C. Finlayson and Steven D. Sroka, Utah Field House of Natural History State Park Museum, Vernal, UT

Thomas Nelsen, Buffalo, NY.

Alternate title:

Our dust collector doesn’t suck!!!

Main Topics

• Background• Evaluation• Comparisons and recommendations• Design• Materials and cost• Installation• Testing the system• Discussion• Conclusions

Background• Why do we need dust control?

Health hazards - Occupational respiratory diseases

(radon, silica dust)  - Irritation to eyes, ears, nose, skin, throat

 Risk of dust explosions and fire Equipment damage Impaired visibilityUnpleasant odors Public nuisance

• Attended First Annual Fossil Preparation and Collections Symposium at PEFO (April, 2008)

Presentations by S. Madsen and G. McCullough addressed the following:

1. The importance of promptly addressing safety hazards in the lab, particularly exposure to rock dust. Long term exposure can cause silicosis and lung cancer!

2. Radon gas particles from rocks and fossils can attach to dust and be inhaled.Long term exposure can cause lung cancer!

• Measuring radioactivity

Radon gas = product of Radium and Uranium decay

1 pCi = 1 trillionth of a Curie1 pCi/L = 2.2 radioactive disintegrations each

minute in 1 L air

Ex: 4 pCi/L = 12,672 radioactive disintegrations in 1 L air in 24 hour period

Evaluation of work environment at the UFH

• Tested for radon in lab and collection storage

Results and observations:

- our measurements = 1.5 - 1.6 pCi/L

- EPA states that there is little short-term risk with

readings between 0.6 – 1.9 pCi/L

- measurements above 4 pCi/L = EPA action level

(4 pCi/L = 200 chest x-rays!)

Radon test recommendations by EPA:

- test in closed building conditions

- keep test kit away from drafts, fans, blowers

- do not test in high humidity (over 55% RH)

- do not place near heat

- levels fluctuate daily and seasonally, do follow up testing!

- test whenever you bring in “hot” rocks and fossils

(Last radon test done at UFH in 1997 = 16.8 pCi/L and 32.5 pCi/L, deaccessioned “hot” rocks and minerals to NMBOM)

• Performed airflow tests on existing system

Results and observations:

- a smoke test showed inefficient airflow patterns

- thermoanemometer read 90 cfm airflow

- accumulation of dust on work surfaces, equipment

- rock dust remains suspended

Dust on lab equipment

• Examined old dust collecting system

Results and observations:

- 1.5 hp unit designed for saw dust removal, not rock dust

- several 90 degree bends in duct work reduced air flow, less efficient

- short intake hoses with limited flexibility

- 2.5” diameter of intake hoses, decreased volume

- location of unit not easily accessible

- only 2 blast gates for adjustment of airflow

Old dust collecting system

Close-ups of old equipment

We need a new system!!!

Comparisons and recommendations• Consulted now retired DNM preparator

S. Madsen and volunteer D. Gray

- DNM’s old system tested in early 90’s by industrial hygienist

- results = serious radon and dust issues

- they did research, contacted other facilities to compare

- DNM got new system in 1996

- larger system, evacs to outside, more remote

- 400 cfm at hose – works great!

- cost ~ $34,000

• Standards ?- no formal standards specific to fossil prep

• What can we do?- use dust collecting unit specific for rock dust

- find some guidelines to design an efficient system

- use OSHA and NIOSH recommendations for transport velocities of particulates

• OSHA and NIOSH recommendations and guidelines

To prevent most industrial dust (granite, silica, limestone, clay, etc.) from settling and blocking ductwork:

- minimum 3,500 - 4000 fpm (304 - 400 cfm) at hose opening

- branches should enter main duct at low angles = decrease drag

- circular ducts instead of rectangular = uniform velocity and distribution

Design

• Things to consider- budget - size of room- appropriate size/type of unit to create cfm

needed (OSHA and NIOSH recommendations)- type, length, diameter of ductwork - city ordinances (noise, dust evac. to outside) - amount, frequency of heavy prep work - # of work stations

• UFH specific considerations and needs- low budget

- more powerful, affordable unit with easy access

- don’t own the building, minimize renovations

- temp. occupancy, minimize the cost

- have small lab space

- chose closed system (no evac.) to avoid nuisance, health hazards to public

- put unit in separate room for less noise

- drew up preferred design

• We called a mechanical engineer!- provided a drawing and system specs

- he did the calculations to make sure our specs met industry standards for safe operation

- he made some spec adjustments and provided us with a final design

Engineering

Final Design

Materials and Cost

Item Company AmountEngineering WHW Engineering $440.00Dust Collector Grainger$3,639.60Electrical (3 phase) BHI $2,055.84Duct work T.S. Heating $2,900.00Hoses (50 ft.) Grainger$312.76Clamps Turner Lumber $23.51Barrels (4) Western Petroleum $192.00Lift rental Basin Rental $30.00Blast gates (4) Industrial Accessories $78.00Hangers for hoses Ace Hardware $55.00

$9,726.71

Installation

6 hoses, 4 blast gates

Screen covering

Testing the airflow of our new system

Comparing length and flex of hose with average airflow (cfm) 

flexed straightenedShort hose (6 ft.) 509 cfm 543 cfm Long hose (12 ft.) 423 cfm 517 cfm

Controls: • thermoanemometer distance = 4 inches• all 4 blast gates were open• used the same short hose and long hose for all tests• average airflow was taken from 10 readings

Comparing length of and distance from the hose with average airflow (cfm)

2 “ 4” 6”Short hose 1189 cfm 509 cfm 239 cfm Long hose 1078 cfm 423 cfm 226 cfm

Controls: • hoses were flexed for all tests• used the same short hose and long hose for all tests • all 4 blast gates were open• average airflow was taken from 10 readings

 

Average airflow 

All 4 gates open 509 cfm  1 short hose gate closed 582 cfm  2 short hose gates closed 680 cfm  2 long hose gates closed 667 cfm  1 short, 1 long hose gate closed 680 cfm  1 short, 2 long hose gates closed 753 cfm  1 long, 2 short hose gates closed 766 cfm   All 4 gates closed 860 cfm

Controls: • thermoanemometer distance = 4 inches• used the same short hose at the station with no blast gates for tests• all 6 hoses in system were flexed• average airflow was taken from 10 readings    

Comparing airflow (cfm) with the number of blast gates open

Discussion

• Interpretation of airflow test results

1. > hose length < airflow2. > hose flex < airflow3. > distance < airflow4. > # blast gates open < airflow5. Little change in airflow when any combo of two gates are closed6. Little change in airflow when any combo of three

gates are closed7. Optimal working distance from hose 4”to 5”

Old Unit1. designed for saw dust2. 1.5 hp motor, 1200 cfm max.3. two 2.5 “ diam. inflexible hoses4. PVC pipes at 90 degree bends5. avg. air flow 90 cfm6. Inefficient!7. did not meet OSHA and NIOSH

recommendations

New Unit1. designed for rock particles2. 10 hp motor, 3200 cfm max.3. six 4 “ diameter flexible hoses4. metal ductwork with 45 degree

bends 5. avg. airflow exceeds minimum

recommendation of 400 cfm6. Efficient! 7. meets OSHA and NIOSH

recommendations

• Final Comparisons

Important contacts and websites National Institute for Occupational Safety and Health (NIOSH)

http://www.cdc.gov/niosh/topics/silica

Occupational Safety and Health Administration (OSHA)

www.osha.gov/SLTC/silicacrystalline/dust/dust_control_handbook.html

Environmental Protection Agency (EPA)

www.epa.gov/radon

Industrial Hygiene Specialist

Consulting Engineer

Conclusions

• tested well below EPA limits for radon exposure

• able to install efficient, affordable system

• new system meets/exceeds OSHA/NIOSH recommendations for dust control

• project can be used as design template for smaller systems specifically for fossil prep.

Don’t take chances! Test for health and safety hazards and don’t wait to take action. This is your life!

Alternate Conclusion: Our new dust collector really sucks!!!

Source: NOAA photo library, NOAA central library; OAR/ERL/National Severe Storms Laboratory (NSSL).

We would like to thank the following for their help and support: BHI electrical, BLM of Utah, Craig Brown, Craig Gerber, Dale Gray, Scott Madsen, Utah State Parks and Recreation, Steve Wadsworth at WHW Engineering.

Acknowledgements