OSHA Inspection: HORSEHEAD CORPORATION

Issued

2011-01-19 00:00:00

Abate by

2011-01-24 00:00:00

Penalty

Initial $7000.00 · Current $7000.00

General-duty citation text

Section 5(a)(1) of the Occupational Safety and Health Act of 1970:  The
employer did not
furnish employment and a place of employment which were free from
recognized hazards that
were causing or likely to cause death or serious physical harm to
employees in that employees
were required to work in close proximity to, and within the vent relief
area and fireball hazard
zone of, explosion-relief vents (or deflagration vents) on a zinc
distillation column, creating the
potential, in the event of an explosion, for the bricks comprising the
vents to burst outward and
contact employees, and flames and/or fireballs to exit the vents and
engulf employees.
(a) Facility, Zinc Refinery Building:  Two explosion-relief vents on the
third floor, and two
explosion-relief vents on the second floor of a zinc distillation column
("B column"), each made
of brick, were located such that bursting bricks, vented flames and
fireballs, and vented gasses
resulting from an explosion in the column would be discharged directly
into
an area in which
employees were required to work.
Among other methods, one feasible and acceptable means of abatement is to
comply with NFPA
68 ("Standard on Explosion Protection by Deflagration Venting") and NFPA
86 ("Standard for
Ovens and Furnaces") with regard to the location of explosion-relief vents
(or deflagration vents)
relative to the location of personnel.  Examples of relevant provisions of
NFPA 68 and NFPA
86 include but are not limited to:
NFPA 86 Section 5.2.8.1 provides: "Bursting discs or panels, mixer
openings, or other
parts of the furnace from which flame or hot gases could be discharged
shall be located
or guarded to prevent injury to personnel."
NFPA 86 Section 5.3.5 provides: "Explosion-relief vents shall be located
or retained so
that personnel are not exposed to injury by operation of the vents."
NFPA 68 Section 4.2.1.3 provides: "Deflagration venting shall be arranged
to avoid
injury to personnel by the vent discharge."
NFPA 68 Section 6.6.2 provides: "Property damage and injury to personnel
due to
material ejection during venting shall be minimized or avoided by locating
venting
equipment outside of buildings and away from normally occupied areas."
Section 6.6.2
also references Section 7.6.4 which explains how to calculate the
dimensions of a
"fireball hazard zone."

Issued

2011-01-19 00:00:00

Abate by

2011-01-24 00:00:00

Penalty

Initial $7000.00 · Current $7000.00

General-duty citation text

Section 5(a)(1) of the Occupational Safety and Health Act of 1970:  The
employer did not
furnish employment and a place of employment which were free from
recognized hazards that
were causing or likely to cause death or serious physical harm to
employees in that the
explosion-relief vents (or deflagration vents) on a zinc distillation
column ("B Column") were
not safely designed according to industry standards, creating the
potential for a partial or
complete failure of the column.
(a) Facility, Zinc Refinery Building:  Two explosion-relief vents on the
third floor, and two
explosion-relief vents on the second floor of a zinc distillation column
("B Column"), were not
safely designed according to industry standards, creating the potential
for a partial or complete
failure of the column  The design deficiencies included: the design of the
vents was not based
on calculated value of the vented deflagration pressure no greater than
two-thirds of the ultimate
strength of the combustion chamber; the brick explosion-relief vents were
not sized based on the
burning velocity of the gaseous fuel inside the vented enclosure; the
opening pressure of the
explosion-relief vents was not tested or documented or maintained at the
worksite; the explosion
vented into an enclosed area rather than an outdoor area that is free and
clear of any obstruction;
and the design calculation data sheets for the explosion-relief vents,
including descriptions of
personnel proximity to the vent relief path, were not developed and
maintained
suitable for
review by an authority having jurisdiction.
Among other methods, one feasible and acceptable means of abatement is to
comply with NFPA
68 ("Standard on Explosion Protection by Deflagration Venting") and NFPA
86 ("Standard for
Ovens and Furnaces") with regard tot he safe design and structure of
explosion-relief vents (or
deflagration vents).  Examples of relevant provisions of NFPA 68 and NFPA
86 include but are
not limited to:
NFPA 68 Section 6.3.1.1 provides "Pstat shall not exceed two-thirds of the
ultimate
strength for the vented enclosure, provided deformation of the equipment
can be
tolerated."
NFPA 68 Section 6.7.2 provides: "A vent closure shall have low mass to
minimize
inertia, thereby reducing opening time," and Section 7.3.3.6 provides the
particular
equation that should have been used to calculate the mass of the vent
closure.
NFPA 68 Section 7.2.2 provides the equation that should have been used to
determine
the size of the vents based upon the type of gaseous fuel.
NFPA 68 Sections 10.2.1, 10.2.2.2, 10.2.2.2.1, and 10.2.2.2.2 require the
designer
and/or manufacturer to test and document the value and tolerance of the
Pstat of a vent
enclosure, and to maintain such documentation.
NFPA 68 Section 6.6.1 provides: "The material discharged from an enclosure
during the
venting of a deflagration shall be directed outside to a safe location."
NFPA 68 Section 11.2 provides: "Data sheets, installation details, and
design calculations
shall be developed and maintained for each vent closure application,
suitable for review
by an authority having jurisdiction that verifies the vent area is
sufficient to prevent
deflagration pressure from exceeding the enclosure strength and identifies
areas
exposed
to potential overpressure, event propagation, and fireball effects during
venting.
Documentation shall include all of the following:... (13) Proximity of
personnel to vent
relief path...(19) Employee training requirements."

Issued

2011-01-19 00:00:00

Abate by

2011-01-24 00:00:00

Penalty

Initial $7000.00 · Current $7000.00

General-duty citation text

Section 5(a)(1) of the Occupational Safety and Health Act of 1970: The
employer did not
furnish employment and a place of employment which were free from
recognized hazards
that were causing or likely to cause death or serious physical harm to
employees in that a
consistent heat-up rate was not maintained during a 10-day heat-up of a
zinc distillation
column which potentially allowed for greater variation in the temperature
of the column.
(a) Facility, Zinc Refinery Building: A consistent heat-up rate was not
consistently
maintained during the 10-day heat-up of B Column beginning on June 30,
2010. On multiple
occasions temperatures in the column were increased at a higher rate that
the company's own
target rate of 4 degrees C/hour as set fourth in the company's written
heat-up schedule. The
results of this inconsistent heat-up rate include, but are not limited to:
multiple instances
when column temperatures were as much as 60 degrees to 100 degrees C
higher than
targeted temperatures as set forth in the company's written heat-up
schedule; and multiple
instances when temperatures in the sump area of the column were more than
100 degrees C
lower than targeted temperatures as set forth in the company's written
heat-up schedule.
Among other methods, one feasible and acceptable means of abatement is: to
implement flow
gauges or regulators on the currently-used flame-safe heaters, to more
accurately determine
the amount of gas flow (and, thereby determining the temperature of the
heat being
produced); to monitor the average temperatures of the six thermocouples
currently available
on the column during heat up; to install additional thermocouples
throughout the column to
better monitor temperature distribution; to set standards among operators
regarding how
much deviation from the target temperature during heat-up is allowable;
and to improve
burner placement to eliminate direct heating or overheating of refractory
trays.