Ammonia Refrigeration Accidents from IchemE’s Accident Database
Number 12744
Date 27 Juni 2000
Source:
CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD, JUNE 28, 2000,
(http://www.chemsafety.gov).
Disclaimer: The Chemical Incident Reports Center (CIRC) is an information
service provided by the U.S. Chemical Safety and Hazard Investigation Board
(CSB). Users of this service should note that the contents of the CIRC are not
intended to be a comprehensive listing of all incidents that have occurred;
many incidents go unreported or are not entered into the database. Therefore,
it is not appropriate to use the CIRC database to perfrom statistical analysis
that extends conclusions beyond the content of the CIRC. Also, although the
CSB never knowingly posts inaccurate information, the CSB is unable to
independently verify all information that it receives from its various sources,
much of which is based on initial reports. CIRC users should also note that the
CSB receives more comprehensive reports about incidents that occur in the
U.S.; comparisons made between U.S. incidents and those in other nations
should take this fact into consideration.
Location
Cadwell, USA
Deaths 0 Injuries 1
Abstract:
A worker was injured by frigid liquid ammonia whilst trying to shut off a
leaking valve during servicing of a refrigeration system. The worker was
treated for a burned forearm.
Approximately twenty-four workers were evacuated from the plant.
Hazardous materials team shut off the valve.
Lessons: [None Reported]
Number 12604
Date 29 April 1999
Source: ENVIRONMENTAL TIMES, VOLUME 6, ISSUE 3, SPRING 2000.
Location
Wales, UK
Deaths 0 Injuries 0
Abstract:
Approximately 40 kg of an ammonia based refrigeration substance was
released from a cooling unit and spilled into a nearby river.
The substance entered a surface water drain nearby, discharging into a small
stream and into the river.
Over 1,000 fish were killed.
The company was fined £2,000 and costs of £200 (2000).
Lessons:
The incident highlights the need for accurate up-to-date drainage plans and
for operators to be fully aware of the potential risks to the environment from
their sites.
Number 3346
Date 06 Juli 1985
Source:
100 LARGEST LOSSES 9TH EDITION, MARSH & MCLENNAN PROTECTION
CONSULTANTS, 1986; LLOYDS LIST, 1985, 8 JUL.
Location
Clinton; Iowa, USA
Deaths 0 Injuries 8
Abstract:
A fillet weld failure on a 2 inch recompressor cylinder discharge line in an
ammonia plant released synthesis gas at 5000 psi. The 50 ft by 350 ft
compressor building rapidly filled with gas before ignition took place 30 - 45
secs later. One of the electric motors driving the four compressors was the
probable source of ignition. The explosion caused widespread damage to the
buildings, the cooling tower, and to an acid plant. A blast resistant control
building sustained no damage.
[damage to equipment]
Lessons: [None Reported]
Number 3243
Date Februar 1985
Source: SEDGWICK LOSS CONTROL NEWSLETTER
Location
Pancevo, YUGOSLAVIA
Deaths 0 Injuries 18
Abstract:
A cloud of ammonia gas occurred at a nitrogen factory, poisoning eighteen
workers. The incident was caused by cooling system failure, which caused a
release of ammonia.
Lessons: [None Reported]
Number 3555
Date Dezember 1983
Source: PLANT / OPERATIONS PROGRESS (VOL. 6, NO 1) JAN 1987
Location
Houston, USA
Deaths 0 Injuries 0
Abstract:
Several firemen and an employee barely escaped from an anhydrous ammonia
explosion in an ice-cream factory. The building engineer was checking the
refrigeration system when he saw a developing vapour cloud, shut down the
liquid line and notified the fire department
While the engineer and the firemen were making preparations to enter, there
was an explosion which blew the building apart. Ammonia vapour issuing
from the basement was controlled by heavy water coverage. The basement
itself was filling with water from fractured sprinkler pipework. The
Hazardous Materials Response Team decided to flood the basement, which
eventually terminated the incident.
It was impossible to determine the exact cause of the devastation. One theory,
that hot light fittings had been shattered on contact with cold ammonia
vapours, was later challenged by the possibility of hot compressor oil being
initially ignited and, in turn, igniting the ammonia vapour.
Lessons:
The following lessons were learnt:
1. Misconceptions regarding ammonia incidents were seriously shattered.
2. The incident proved that ammonia can burn violently.
3. A new attitude to handling large ammonia leaks was brought about.
4. Remote isolation and proper ventilation is a pre-requisite for fire teams'
intervention.
Number 10742
Date 15 August 1982
Source: ICHEME
Location
Unknown
Deaths 0 Injuries 2
Abstract:
Ammonia leaked from a refrigeration unit in a wholesale food warehouse. The
fumes spread through several blocks before fire fighters succeeded in stopping
the leak, nearly three hours after it began. Two fire fighters were hospitalised
for treatment after being overcome by fumes.
Lessons: [None Reported]
Number 10316
Date 19 März 1970
Source: AMMONIA PLANT SAFETY, A.I CHEME, VOL13, 1971
Location
Oulu, FINLAND
Deaths 0 Injuries 0
Abstract:
A forged steel chamber, in one of the effluent coolers of an ammonia plant
failed explosively.
The escaping gas caught fire. Extensive damage was caused to the plant and
surrounding buildings. The purpose of the heat exchangers was to condense
ammonia and cool air that was supplied to an air cooler. Prior to installation
and operation, the condenser forgings had been heat treated, hydrostatically
pressure tested and the welds tested with dye penetration. They had operated
normally for about two and a half months prior to the incident. The failure
originated at an overlay weld on the chamber wall.
Lessons:
Investigations indicated that the explosion was caused by "brittle failure" of
the forging. The reasons for this were:
1. Selection of the material used in preparation of the forging.
2. Light forging
3. Defective heat treatment
The following recommendations were made:
1. Carbon content of the steel less than 0.15% to improve welding properties.
2. Vanadium 0.17% for acceptable hardness.
3. Heat treatment sufficient to ensure adequate toughness, e.g. temperature
over 600 degrees C for many steels.
4. Avoid hydrogen cracking during welding, e.g. by maintaining preheating
temperatures for a few hours, to allow hydrogen to be released.
5. Overlay welds should not extend as far as the wall of the forged chamber.
Number 7290
Date Date Unknown
Source: LOSS PREVENTION BULLETIN, 083, 11-12.
Location
Unknown
Deaths 0 Injuries 0
Abstract:
Scheduled maintenance of a refrigeration unit was in progress. The first
phase involving work on the unit's compressor and evaporator had been
completed. In order to allow work to continue, the local engineering
department (mechanical) had requested that the ammonia liquor stored in the
condenser liquid receiver unit be transferred to the evaporator. The
procedures to be used in this transfer were agreed, the need for a leak test
before admitting ammonia (NH3) was not identified.
On the day of the incident, brine solution was fed to a refrigeration unit's
evaporator which was rectified by the shift fitter. The process supervisor
started the transfer of liquid ammonia after the brine solution had been
circulating to the evaporator for one hour. Later the liquid receiver's outlet
valve was closed. An ammonia leak was detected at the flange after the open
valve on the evaporator side. The process supervisor donned a self-contained
air set and attempted to tighten the flange, although local visibility was poor.
He was unsuccessful as the leaking ammonia froze his gloves making
manipulation impossible. The shift manager was notified of the ammonia
release, and also personnel on the control panel and on arrival found the panel
operator in the air line respirator. Measures were taken to prevent anyone
entering the building and the operation of the plant was stopped.
Lessons:
The following recommendations were made:
1. Following mechanical maintenance and/or repair on the units, liquid
ammonia should not be introduced into the appropriate equipment before a
leak test is carried out.
2. A formal written procedure should be issued specifying a leak test method
and identifying the role of engineering and production department personnel.
3. It needs to be re-iterated that flange sealing faces should be in good
condition before making a joint.
4. It should be re-iterated that written operating instructions must be issued
for non-standard operations in the format agreed for normal operation
instructions.
Number 11456
Date Date Unknown
Source: PETROLEUM REVIEW, OCTOBER 1986.
Location
Unknown
Deaths 0 Injuries 1
Abstract:
A leak of ammonia was discovered in the refrigeration area of an ammonia
plant, the vapour cloud being emitted from a vent on the refrigeration
compressor. An attempt was made to control and dilute the emission. After
about ten minutes a site fireman, wearing a full-face mask, with ammonia
absorbent canister, collapsed. He was removed from the scene and taken to
recover in fresh air.
On examination of the filters in the ammonia canister, taken from the mask, it
was found that they were soaked with water, the fibres had expanded and
therefore air had been unable to reach the user. The fireman had been
working behind a water fog curtain.
[refrigeration unit, gas / vapour release, asphyxiation]
Lessons:
A test identified that a teaspoonful of water was sufficient to clog the filter
and prevent airflow.
Number 7956
Date Date Unknown
Source: ICHEME
Location
Unknown
Deaths 0 Injuries 0
Abstract:
As the morning shift was taking up its duties a leak of ammonia was reported
in the refrigeration area of the ammonia plant. The Fire/Safety department
responded and found an ammonia vapour cloud was issuing from a vent on the
refrigeration compressor. The fire department made an initial attempt to
control and dilute the vapour cloud using the well tried method of water fog.
After approximately 10 minutes one of the fireman who was wearing a full
face mask with ammonia absorbent canister collapsed. He was removed
instantly and recovered within minutes of being taken to fresh air.
After the incident had been controlled an investigation was started as to why
the man had collapsed.
The immediate opinion of the operation staff was that the man had either not
put on his mask properly or had not removed the seal on the canister thus
indicating poor training of this man.
The latter reason was disposed of as the man had already been in the vapour
cloud for 10 minutes with no ill effect. Therefore he must have removed the
canister seal prior to donning the mask.
The first cause of lack of training was taken quite hard by the safety
department who felt that the man, who had been with them for 2 years, was
quite adequately trained. They then re-enacted the incident with the man who
was involved to ascertain the cause of the collapse. No apparent cause was
found until they decided to cut open the canister to check the level of ammonia
contamination of the filters.
The examination showed that where the man had been working behind a
water fog curtain the filters in the canister had become sodden with water,
the fibres had expanded and oxygen was prevented from reaching the user.
Tests showed that only a small amount of water (1 teaspoon) was sufficient to
clog the filter and prevent air flow.
The plant safety department has since issued a directive that air supplied
Breathing Apparatus must be used at all times when tackling toxic gas releases
and not filtration type of canisters which could become clogged with water.
Lessons: [None Reported]