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Appendix C
251
APPENDIX C Recommendations of NAS Panel on Grain Elevator Explosions [Anon. (1980)] First Priority Actions Φ
Continue research on methods for reducing the dust concentration in legs to a level below the lower explosive l i m i t .
t
Establish a housekeeping program involving a mechanical dust collection system supplemented by manual or other means.
t
Conduct rigorous preventive maintenance, especially on all parts of bucket elevators.
t
Use a pre-established and enforced permit procedure whenever welding, cutting, or other op^n flame work i s to be done.
t
Incorporate a system to indicate belt slippage and misalignment.
•
Incorporate a method to check frequently the temperature and vibration of c r i t i c a l bearings.
t
Use devices to extract foreign materials from the incoming grain stream.
•
Ground all conveying and electrical equipment.
Second Priority Actions §
Examine the overall functions of mills and elevators to develop a totally new system less subject to the hazards of dust explosions.
t
Control dust generation and airborne dust at all discharge points.
t
Notify all plant managers that safety i s their responsibility. If authority i s delegated it must be to an employee who reports directly to the plant manager.
•
Apply state-of-the-art techniques to reduce the concentration of airborne dust in and emanating from elevator legs.
•
Establish an information center to distribute actively all available information on elevator and mill dust explosions and their causes and prevention.
•
Establish a f i r e facility.
§
Conduct research to develop economic uses for collected grain dust.
•
Locate hammer m i l l s , other grinding equipment, and their dust collection systems separate from the main f a c i l i t y .
•
Eliminate all nonessential horizontal surfaces.
and explosion prevention
grain transfer
and
training program at each
252 Treat the avoidance of dust explosion hazards as an i n i t i a l design c r i t e r i a in the construction of new mills and elevators and the modification of existing structures. Continue research on methods for reducing dust concentrations below the lower explosive limit in enclosures other than l e g s . Investigate and report on explosions in a manner that reflects the recommendations made by the panel in i t s report, "The Investigation of Grain Elevator Explosions," Report NMAB 367-1. hird Priority Actions \
Follow, to the extent practical, the National Fire Protection Association's standard on explosion venting (No. 68) for all enclosures. Concrete structures should be vented by windows or other openings of the size dictated by this standard.
ι
Establish a government and industry group to aid in developing and updating explosion prevention regulations for elevators and m i l l s .
ι
Quantify housekeeping standards for cleanliness f a c i l i t i e s that will prevent fires and explosions.
ι
Coat all nonhorizontal surfaces exposed to airborne dust with a material that will prevent the build-up of layered dust.
)
Investigate the effect of electrostatics and absolute humidity on the explosion hazard, including an examination of conveyor belt conductivity and the charging of ungrounded conductive structures.
ι
Apply state-of-the-art techniques to reduce the concentration of airborne dust below the lower explosive limit where possible in enclosures other than legs.
ι
I f dust i s returned to the grain stream do i t manner.
ι
Use only equipment and installation standards meeting national Code requirements.
in
grain-handling
in the least hazardous Electrical
APPENDIX C Recommendations of NAS Panel on Grain Elevator Explosions [Anon. (1980)] First Priority Actions Φ
Continue research on methods for reducing the dust concentration in legs to a level below the lower explosive l i m i t .
t
Establish a housekeeping program involving a mechanical dust collection system supplemented by manual or other means.
t
Conduct rigorous preventive maintenance, especially on all parts of bucket elevators.
t
Use a pre-established and enforced permit procedure whenever welding, cutting, or other op^n flame work i s to be done.
t
Incorporate a system to indicate belt slippage and misalignment.
•
Incorporate a method to check frequently the temperature and vibration of c r i t i c a l bearings.
t
Use devices to extract foreign materials from the incoming grain stream.
•
Ground all conveying and electrical equipment.
Second Priority Actions §
Examine the overall functions of mills and elevators to develop a totally new system less subject to the hazards of dust explosions.
t
Control dust generation and airborne dust at all discharge points.
t
Notify all plant managers that safety i s their responsibility. If authority i s delegated it must be to an employee who reports directly to the plant manager.
•
Apply state-of-the-art techniques to reduce the concentration of airborne dust in and emanating from elevator legs.
•
Establish an information center to distribute actively all available information on elevator and mill dust explosions and their causes and prevention.
•
Establish a f i r e facility.
§
Conduct research to develop economic uses for collected grain dust.
•
Locate hammer m i l l s , other grinding equipment, and their dust collection systems separate from the main f a c i l i t y .
•
Eliminate all nonessential horizontal surfaces.
and explosion prevention
grain transfer
and
training program at each
252 Treat the avoidance of dust explosion hazards as an i n i t i a l design c r i t e r i a in the construction of new mills and elevators and the modification of existing structures. Continue research on methods for reducing dust concentrations below the lower explosive limit in enclosures other than l e g s . Investigate and report on explosions in a manner that reflects the recommendations made by the panel in i t s report, "The Investigation of Grain Elevator Explosions," Report NMAB 367-1. hird Priority Actions \
Follow, to the extent practical, the National Fire Protection Association's standard on explosion venting (No. 68) for all enclosures. Concrete structures should be vented by windows or other openings of the size dictated by this standard.
ι
Establish a government and industry group to aid in developing and updating explosion prevention regulations for elevators and m i l l s .
ι
Quantify housekeeping standards for cleanliness f a c i l i t i e s that will prevent fires and explosions.
ι
Coat all nonhorizontal surfaces exposed to airborne dust with a material that will prevent the build-up of layered dust.
)
Investigate the effect of electrostatics and absolute humidity on the explosion hazard, including an examination of conveyor belt conductivity and the charging of ungrounded conductive structures.
ι
Apply state-of-the-art techniques to reduce the concentration of airborne dust below the lower explosive limit where possible in enclosures other than legs.
ι
I f dust i s returned to the grain stream do i t manner.
ι
Use only equipment and installation standards meeting national Code requirements.
in
grain-handling
in the least hazardous Electrical