SSE MFG., INC. - TONY'S PIZZA SERVICE - Executive Summary
Schwan's has historically placed a high priority on chemical |
safety. The corporate environmental compliance manager has been
assigned overall responsibility for chemical safety in general and
for ammonia refrigeration safety in particular since 1991.
Schwan's maintains 3 - shift coverage of emergency responders
trained to the 24-hour technician level at all facilities with
ammonia refrigeration systems covered by this rule.
The Salina, KS facility manufactures frozen pizza. Anhydrous
ammonia is used in the refrigeration system at this facility.
Ammonia is the most efficient and environmentally compatible
refrigerant available. Although it is toxic at high concentration
and is an irritating gas, it is not a cumulative metabolic poison,
does not cause cancer or other dread diseases and does not cause
lasting environmental damage. The refrigeration system at this
facility contains about 112,000 pounds of ammonia.
The Salina, KS facility uses liquid propane as a back-up fue
natural gas-fired ovens. The inventory of 100,000 pounds of
propane is normally in storage and is used only during periods of
extremely cold weather.
Schwan's calculates ammonia worst case release scenarios using the
Model RMP for Ammonia Refrigeration, May 1996. All Schwan's
manufacturing facilities are located in areas that meet the
definition of "urban". Schwan's has chosen to calculate worst case
release poundage for the largest high-pressure receiver in the
system, filled to full calculated hydraulic capacity. Reduced
volume for administrative controls was not used, since the
described scenario would probably occur only as a result of a
catastrophic vessel rupture caused by a total filling of the
vessel, closure of all vessel block valves, failure of all
pressure relief valves, with a simultaneous increase in liquid
temperature sufficient to overpressure the vessel to the point of
It is the professional judgement of Schwans Environmental Health
d Safety Department that a release rate of 400 lb./min. should
be used as an alternate case scenario in lieu of the 100 lb./min.
rate suggested in the Model RMP.
The "urban" site condition will be used.
Based on the above, the worst-case ammonia release scenario for
the Salina, KS facility will be 34,000 pounds released over a 10-
minute period. The alternate case will be a release rate of 400
pounds per minute. Both scenarios have off-site impacts.
For propane, worst case and alternate case scenarios were
calculated using RMP Offsite Consequence Analysis Guidance, May
1996, for flammable substances.
Worst case assumes that the propane tank is 80% full. A vapor
cloud explosion occurs involving 100% of the material in the tank.
The consequence distance is to an overpressure of 1.0 psi.
Alternate case assumes that the propane tank is 80% full and that
the tank contents are released over a period of 10 minutes at a
constant rate. The consequence distance is to Lower Flammab
Limit (LFL) of 35 mg./L., "D" atmospheric stability and wind speed
of 3.0 m./sec. In order to achieve a more conservative result,
rural conditions are used.
The ammonia refrigeration system is covered by the OSHA Process
Safety Management (PSM) rule, 29 CFR 1910.119.
Although the Salina, KS facility has experienced 4 releases which
were reported under EPCRA Section 304 in the five years beginning
21 June 1994, none was more than 500 pounds and none resulted in
onsite or offsite casualties or off-site evacuations.
The Salina, KS facility maintains a 3-shift emergency response
team, trained at the 24-hour technician level. The team numbers 24
members. The training is conducted by the Corporate Environmental
Compliance Manager. The training is designed with a heavy emphasis
on ammonia safety, mechanical isolation, personal protective
equipment up to use of Level `A' suits and interaction with an
incident command system (ICS). Copies of emergency plans are filed
h the Fire Department and annual facility walkthroughs are
conducted with Fire officers. Preplanned command posts and staging
areas have been designated and Incident Command transfer and
liaison functions have been established. A post-incident
debriefing is conducted after each incident.
Since a continuous improvement philosophy is deeply imbedded in
the Schwan's corporate culture, improvements in system safety are
implemented as a result of employee-based Total Quality Management
(TQM) teams, a designated PSM team and as a result of system
engineering modifications and extensions. Post incident
debriefings and incident investigations are used to identify
additional improvements to system safety.