C. M. Consulting
P.O. Box 407
Odell, Oregon 97044
C. M. CONSULTING
A Division of Cliff Mansfield Incorporated
ASPHALT PLANT SAFETY
In PART 1 we
discussed lockout-tag out accidents, burner safety issues and the dangers of
poor maintenance practices. In PART 2 we will address some of the other areas of
potential hazards and the consequences of taking them lightly.
Numerous other dangers lurk around a plant, awaiting the unwary. Electrical
shock injury is common, as are injuries from falls and accidents resulting from
the conflicts between the rolling stock around the plant. Burns from hot asphalt
oils are also fairly common, though rarely fatal. Portable asphalt plants are
especially vulnerable in these areas because of the labor intensive environment
and the number of people involved when they are being moved.
The following accidents occurred at portable asphalt plants in the past five
years. Again, they weren't the only ones.
A portable drum plant was being torn down in preparation for a move to a new
location when a 30 year old plant mechanic was severely injured by a fall from
the crane ball he was riding. The victim had been on top of the asphalt silo
disconnecting the slat conveyor and then rigging the picking cables for the
holding silo. Since the silo had no access ladder the man was forced to find
another way to the ground after hooking a 100 ton Link-Belt crane's line to the
silo rigging. As they had done many times in the past, workers moved a 9 ton Pettibone crane next to the silo and the victim climbed onto the ball. On the
trip down he lost his grip on the greasy cable and fell twenty feet to the
ground. This accident was personally witnessed by the author who was at the
facility to train a new operator for the company. While supervising the plant
tear-down, the author became busy on another issue and failed to spot this bit
of stupidity until it was too late to stop it.
A forty year old
plant operator was killed when he was electrocuted while unwiring a 10
horsepower motor on a feeder collecting conveyor. The plant, a Boeing drummer,
was running two shifts at the time. The night operator had experienced problems
with the belt's starter. This resulted in one set of starter contacts being
burned out and rendered inoperable. No replacement contacts were available at
the time, so to get running the operator simply wired around the bad set of
contacts, leaving one leg hot at the motor all the time. Around mid-day on the
next shift the motor lost a bearing and began to squeal, requiring its immediate
replacement. The day operator, unaware of the night man's wiring modification,
failed to turn off the circuit breaker to the motor and lock it out as required
by law. Unfortunately, he was standing in two inches of water when he unwired
the hot leg and as a result was electrocuted to death.
An 18 year old novice ground-man was severely injured when he attempted to
grease the head roll on a collecting conveyor. The chain driven unit was running
at the time and the guard had been removed earlier in the day to facilitate the
replacement of a broken chain. In order to grease the drive side of the head
roll the victim had to reach through the moving chain to access the bearing
which was hidden behind the drive sprocket. When he attempted to pump the grease
gun his hand became entangled in the moving chain. In an instant the victim's
hands were drawn into the chain's pinch-point and around the drive sprocket.
Both hands were severely mangled, requiring many operations including the
amputation of several fingers on each hand. He will be on SAIF (state accident
insurance fund) disability for the rest of his life.
In the final analysis, all three of these accidents were due, in part, to
negligence on the part of the victim. And to a greater degree on the failure of
their respective companies to provide clear and strict guidelines for use in the
situations encountered by the each of the victims.
It is simply illegal to ride any
cable on a crane unless a suitable man-basket and safety restraint belt are
used. This particular plant, an older Boeing, had been moved numerous times over
its career. There was plenty of time to install an approved safety ladder to
provide access to the top of the silo. At this company it was an accepted
practice to ride the crane ball. Evidently, no one gave any thought to the
consequences until after the accident. The truly baffling part of this incident
is the fact that the OSHA required safety equipment was on the back of a truck
within fifty feet of where the victim hit the ground. The equipment was provided
by the company who supplied the 100 ton Link-Belt crane and specifically ordered
by the author for use in the very situation that led to this accident.
On a related topic: People routinely climb around on asphalt plants while they
are being torn down, and surprisingly few of them are even aware that OSHA
regulations require the use of an approved safety restraint belt whenever a
person is over six feet from the ground. Other people shy away from their use
because the devices are awkward and uncomfortable. This seems a petty
consideration when compared with the discomfort that results from a high speed
impact with the ground after falling from the top of an asphalt holding silo. If
comfort were a valid consideration in safety issues one could speculate that
there would be a lot more corpses laying around. Few people voluntarily wear
hard-hats, safety glasses and gloves.
While failure to follow published
OSHA Lockout-Tag out regulations was the direct cause of this accident and that
issue was discussed in PART 1, this incident is included here to demonstrate the
indifference with which some people approach potential electrical shock hazards.
In this case the victim didn't even bother to turn off the circuit breaker as
required by even the most basic safety concepts. Instead, he pressed the motor's
stop button and opted to rely on the contacts in the starter. While we will
never know for sure, it is easy to speculate that his reasoning was probably
that as long as no one pressed the start button for the collecting conveyor the
motor wiring would be dormant. He was wrong: dead wrong.
A contributing factor in this accident was the failure of the night operator to
inform the day operator of the potentially lethal condition he had created when
he by-passed the motor's starter contacts. Communication is a key safety issue
at any HMA (hot mix asphalt) facility. The simple practice of keeping a daily
plant diary may have saved a life in this case.
Two things combined to cause this
accident. First, the ground-man was not sufficiently trained in his new job to
realize the dangers posed by moving equipment, especially chain drives. Being
young and eager to impress his new boss the kid made a poor choice that will
haunt him for the rest of his life.
The second and more important issue in this case is the failure to replace the
guard over this drive unit when needed repairs were finished earlier in the day.
With trucks backed up and the paving superintendent screaming for hot-mix it's
not hard to see how the pressure of production quotas probably influenced the
operator's decision to leave the guard off. In retrospect, it was a decision
everyone involved regretted. OSHA levied heavy fines in this incident and, of
course, the lawsuits continue. This particular company instituted a new policy
as a result of this accident: Under no circumstances shall a piece of equipment
be operated without the appropriate guards in place. PERIOD! There are no
exceptions to this rule. Any employee found in violation of this rule is subject
to immediate and final termination. Perhaps this is a rule that should be
adopted by every asphalt company in this country.
Other Safety Issues:
One area of safety that is routinely compromised at portable asphalt plants is
the conflict between truck traffic and the needs of the loader operator to
access his stockpiles. Small pits, filled with the aggregate for coming jobs,
sometimes offer precious little space to set-up a plant. Compromises must often
be made that can and do jeopardize safety. One common practice is to run the
truck traffic behind the loader at the feeders until enough aggregate can be
used up to permit the construction of an alternate path. In the heat of battle
the loader operator is a busy person. Sometimes, hurried past the point of
conscious thought by the need to keep up with the plant, the loader operator
backs away from the feeders without checking behind the machine. Since loaders
have the right-of-way in almost all pits, the operator gets away with this most
of the time. But not always. It seems obvious that the utmost care must be
exercised during the time the trucks are vulnerable, yet each year trucks are
wrecked and their drivers hurt.
One method of combating this problem is to have a meeting prior to the start-up
of operations on the first day. The loader man and all truck drivers should
discuss the ways to keep their respective activities safe for the others and
work out a plan that is acceptable to everyone involved.
One suggestion: a common C.B. (citizen band) radio in the loader and one in each
of the trucks can go a long way toward eliminating conflicts. Again,
communication is often the key to safety.
Another potentially dangerous activity around portable plants is the handling of
hot asphalt oils. Each year people are burned when they are careless, equipment
fails or hot oil is forced into plugged lines. A hose that fails explosively
under high pressure can send a surprising amount of oil in a large radius, to
the peril of anyone unfortunate enough to be standing near. Properly maintained
and operational pressure relief valves can help eliminate a lot of the risks.
Also, a remote start-stop station for the off-loading pump can be a true asset
if an accident does occur and spraying oil drives everyone away from the area.
The flame used to heat stubborn pumps, lines and off-loading hoses can sometimes
cause problems, especially in those area where housekeeping is lax. Asphalt oil
fires are difficult to extinguish, once they get going. The best way to prevent
fires is to deny them a chance to get started in the first place. Oil messes
should be cleaned up immediately. Any leaking fittings, hoses or shaft seals
should be repaired or replaced at once. In addition, a liberal sprinkling of
five and ten pound fire extinguishers around the off-loading area will go a long
way toward minimizing the damage should an incident occur. A shovel and a modest
pile of sand can also provide some insurance, and are useful in cleaning up oil
The issue of careless people is a somewhat more difficult to deal with, since
some folks only learn in the aftermath of an accident. If a person is
consistently careless and puts themselves and others at risk, perhaps it's time
to replace the guy, even if he is Aunt Mabel's favorite son.
One common thread in all the accidents discussed in PARTS 1 & 2 was a disregard
of safety issues in deference to production pressures. Asphalt plant operators
often feel tremendous pressure to produce by any means possible. Unfortunately,
this shifts the focus off safety and onto money. Perhaps a clear-cut set of
guidelines dealing with company policy on safety issues should be drawn up and
distributed to everyone involved with the plant. Be sure to include the Paving
Superintendent. This individual can exert enormous pressure on the plant
operator without even realizing that he is doing it.
Everyone wants to do a good job and will sometimes go to great lengths
to get results. Often, to that end, things are done that normally would not even
be considered. Once again, communication is the key to safety.
When dealing with safety issues, one must keep in mind the fact that you need to
be safe all the time-- you need only be careless once for tragedy to strike.
For additional information on this subject
or help with any problems encountered
contact Cliff Mansfield,
7:30am to 9:00pm Pacific Standard Time.
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