The components of a housekeeping program primarily include:
1. Written instructions
2. Frequency of inspections
3. Frequency of cleaning
4. Methods of cleaning
5. Spills and leaks
6. Dust control equipment
Identify "priority" housekeeping areas in grain elevators that are known to be potential sources of ignition. OSHA requires that these include: Floor areas within 35 feet of inside bucket elevator legs, enclosed areas containing grinding equipment, and enclosed areas containing grain dryers located inside the facility.
Address the methods for removing grain spills from work areas, which include" Sweeping, shoveling, and vacuuming, blow down and/or wash down. Note that the use of compressed air to remove dust is permitted by OSHA only when all machinery that presents a source of ignition in the area is shutdown, and all other know potential ignition sources are removed or controlled.
Clean and inspect priority areas daily. Other areas inside the grain elevator but outside of the priority housekeeping areas should be inspected and cleaned at least weekly, or more frequently if needed. Surrounding outside areas should be checked weekly and cleaned as needed.
Report and clean up spills and leaks promptly. Resolve the cause of leaks and spills before resuming operations. Dust collection systems need to be maintained on a regular basis to remain effective. Leaks need to be repaired as soon as possible and dust collection bags need to be replaced as needed. Employees should also notify their supervisor or manager of any housekeeping concerns at any time.
Grain dust is the main source of fuel for explosions in grain handling facilities.
The OSHA grain handling standard allows a maximum accumulation of no more than 1/8th-inch in priority housekeeping areas. If dust accumulations exceed the 1/8th-inch action level, means or methods must be initiated immediately to remove such accumulations.
The employer may use alternative means to the 1/8th-inch action level so long as the alternative can be demonstrated to provide equivalent protection from explosions.
The NGFA expands on an example of a housekeeping program in its Safety and Health Compliance Manual, which can be found here.
When combustible dusts ignite, there are often two explosions, known as primary and secondary explosions.
The primary dust explosion is the first explosion. It occurs when there is a dust suspension in a confined space (such as a container, room, or piece of equipment) that is ignited and explodes.
The primary explosion will shake other dust that has accumulated. When this dust becomes airborne, it also ignites. This secondary dust explosion is often more destructive than the primary one.