Ammonia Site Evacuation

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Ammonia Site Evacuation 
To stay or not to 
stay?
Adam Bowey - Grenco Refrigeration Ltd. 
To Stay or Not To Stay
AGENDA
• Ammonia Emergency Evacuation 
Procedures
• Ammonia Emergency Evacuation –
Training Validation
• Ammonia Procedure
• Case Studies:- To stay or not to stay?
Adam Bowey - Grenco Refrigeration 
Ltd. 
Ammonia Emergency Evacuation 
Procedures
• Why do we need an emergency 
evacuation procedure?
• Safety devices and strict design makes the 
risk of a leak very small, however 
additional measures must be in place in 
the unlikely event of a major ammonia 
leak.
Adam Bowey - Grenco Refrigeration 
Ltd. 
Ammonia Emergency Evacuation 
Procedures
• How will I know that there has been an 
ammonia leak?
• Leak sensors are sited all round the 
refrigeration plant, in the event of a leak an 
alarm will sound.
• An announcement will be made to all staff. 
The announcement will advise the course of 
action to be followed. On no account are you 
to leave the building until you are told to do 
so.
Adam Bowey - Grenco Refrigeration 
Ltd. 
Ammonia Emergency Evacuation 
Procedures
• Will I be able to smell ammonia in the main 
building?
• Probably not, if a leak does occur it is most likely that it 
will be in the refrigeration plant room or in the roof 
void. These areas have automatic extract ventilation 
that will discharge ammonia at roof level, ammonia 
gas is lighter than air it will disperse in the 
atmosphere.
• What if I smell ammonia where I am working?
• Evacuate to the nearest adjacent room with your 
colleagues and report the incident. Note that 
ammonia can be detected by smell at very low 
concentrations, much lower than those that cause 
harm This provides useful early warning system
Adam Bowey - Grenco Refrigeration 
Ltd. 
Ammonia Emergency Evacuation 
Procedures
• Why do we not evacuate the building?
• Ammonia is a liquid, which very quickly turns to gas 
when it comes in contact with air, and as such will be 
carried by any wind. Depending on the area the leak is 
and in the direction of the wind, you may be able to 
continue working, or you may be asked to assemble in 
a particular area of the building, as it may be safer to 
stay inside.
• Where will we assemble?
• There are designated site assembly points. 
Adam Bowey - Grenco Refrigeration 
Ltd. 
Ammonia Emergency Evacuation 
Procedures
• How will we know where to assemble?
• The assembly point you have to go to will depend on the wind 
direction because ammonia is a gas. The announcement will 
tell you exactly which assembly point you have to go to. 
Remember the direction of the wind will not always be the 
same. 
• If we evacuate what route do I use?
• Unlike a fire evacuation you may not be able to use the most 
direct or quickest route to an evacuation point, you will be 
given clear directions at the time as to which route you should 
use.
• Do remember that as with a fire evacuation, you must not stop 
to collect personal belongings, run, or re-enter an affected 
area or the building until you have been given clear 
instructions that it is safe to do so.
Adam Bowey - Grenco Refrigeration 
Ltd. 
Ammonia Emergency Evacuation 
Procedures
• What part do the emergency services have in this 
procedure?
• In the event of ammonia leak the Fire Brigade will be called to 
site, on arrival the Senior Fire Officer will assume command of 
the situation and will advise management on staff movements 
around the site, and will issue instructions to the maintenance 
contractors with a view to making the plant safe.
• I am a driver what do I do?
• In the event of a leak a member of the emergency team will 
collect company drivers and direct them to an assembly point.
• The emergency team will collect 3rd party drivers and direct 
them to an assembly point.
Adam Bowey - Grenco Refrigeration 
Ltd. 
Ammonia Emergency Evacuation 
Procedures
SUMMARY:
• Ammonia leak incidents are rare.
• Assembly Points and Evacuation Routes will be 
announced
• Listen carefully to all Assembly and Evacuation 
instructions.
• Do not evacuate the building unless instructed to 
do so.
• If assembly or evacuation is ordered ensure that 
you are aware of the appropriate Assembly 
Point(s) and the Route(s) to take to evacuate the 
Adam Bowey - Grenco Refrigeration 
Ltd. 
AMMONIA EMERGENCY EVACUATION 
Staff Training Validation
• How will you know if there has been an ammonia leak?
• In the event of an ammonia leak what will you do?
• Where are the ammonia leak assembly points inside the building?
• Where are the ammonia assembly points outside the building?
• How will you know which point to go to?
• What dictates which assembly point you have to go to?
• You must not do what, until given a clear instruction?
• Trainees Signature: ______________________________________
Adam Bowey - Grenco Refrigeration 
Ltd. 
Ammonia Procedure
• 1.0 Introduction
• In the unlikely event of a serious leak of ammonia it is 
vital that immediate action is taken to minimise risk to 
life or property.
• To this end the site that has ammonia refrigeration 
shall produce Ammonia Alarm - Emergency 
Response Instructions
• In general the procedure for this site regardless of 
staffing or configuration shares the essential steps of 
internal notification, external notification and 
evacuation. 
Adam Bowey - Grenco Refrigeration 
Ltd. 
Ammonia Procedure
• 2.0 Probability of Ammonia Leaks
• The food manufacturer’s ammonia refrigeration system is 
designed, built, maintained and inspected to strict regulatory 
and industry standards. Catastrophic failure or serious leaks 
in plants to these standards are very rare. Ammonia plants 
are constructed entirely from steel pipework that is much less 
prone to leakage than the copper pipework normally used with 
other refrigerants.
• Minor leaks, mainly in the refrigeration plant room (less often 
in the condenser location) occasionally occur. These leaks 
are usually from shaft seals, pipe flanges or valve stems. 
Plant rooms containing ammonia equipment are fitted with 
ammonia sensing alarms that automatically start ventilation 
systems that vent ammonia gas to atmosphere.
Adam Bowey - Grenco Refrigeration 
Ltd. 
Ammonia Procedure
• 3.0 Ammonia Hazards 
• Ammonia gas is toxic and in a fairly narrow band of concentration 
with air (160,000 to 270,000ppm by volume) is flammable and 
explosive.
• Ammonia’s pungency is however a significant advantage as it can 
be detected by smell at concentrations of 5ppm upwards and 
therefore warns personnel against remaining in a harmful 
concentration. 
• Short term exposure to concentrations of about 200ppm will cause
irritation and discomfort to the mucous membrane and the eyes but 
with no lasting consequences. Exposure to concentrations above 
1500ppm will damage or destroy body tissue whilst exposure to 
2500ppm and above increases the risk of fatality
Adam Bowey - Grenco Refrigeration 
Ltd. 
Ammonia Procedure
• 4.0 Ammonia Leak Detection
• Automatic Leak Detection is installed in refrigeration plant 
rooms and where applicable in roof voids via two stage 
alarms: -
• Level 1: - This level is set at a maximum 500ppm
• Level 2: - This level is set at a maximum 30,000ppm (3% by 
volume) and denotes a major leak. 
• Human Leak Detection at 5ppm upwards is more sensitive 
than the automatic equipment and provides a valuable early 
warning system
Adam Bowey - Grenco Refrigeration 
Ltd. 
Ammonia Procedure
• 5.0 Plant and Equipment
• The design and operation of ammonia refrigeration plants is 
subject to number of regulatory and standards requirements 
including, but not limited to: -
• HSEGuidance Note PM81 (Published 1995) 
• Construction (Design and Management) Regulations 2007 
• Pressure Systems Safety Regulations (2000) – Written Scheme 
of Examination required
• EC Pressure Equipment Regulations 1999 (PED)
• BS EN 378:2008 Parts 1/2/3/4 Refrigerating Systems and Heat 
Pumps – Safety and Environmental requirements. (Part 1 not 
issued)
• Institute of Refrigeration – Safety Code for Compression 
Refrigerating Systems Utilising Ammonia (under revision)
Adam Bowey - Grenco Refrigeration 
Ltd. 
Ammonia Procedure
• 6.0Emergency Response Procedures
• On actuation of alarm, emergency team 
informed.
• Call out to specialist refrigeration contractor. 
• Emergency team call fire brigade.
• Establish wind direction and tailor evacuation 
plans accordingly. (wind sock)
• Emergency team will announce on the action 
to be taken. 
Adam Bowey - Grenco Refrigeration 
Ltd. 
Ammonia Procedures
• 6.0 Emergency Response (continued) 
• Emergency team will check ventilation systems, doors and 
windows.
• Ammonia alarm sounder must be different from fire alarm 
• Call an ambulance if aware of injuries and ensure access 
available for emergency vehicles.
• Emergency team and specialist contractor must stand by to 
assist fire brigade
• Specialist contractor may effect repairs if safe 
• Employees and visitors must ONLY return to evacuated areas 
after being instructed to do by emergency support team or fire 
brigade. 
• Additional procedures will be required for out of hours 
Adam Bowey - Grenco Refrigeration 
Ltd. 
Ammonia Procedure
• 7.0 Ammonia Emergency Action Plan
• Isolation of the leak and the rescue of any persons in the leak 
area with the assistance of the emergency services
• Location of plant rooms and associated pipework
– Site general arrangement plan of ammonia plant and pipework. 
– Plant emergency shut down procedure
– Risk Assessment of each area showing what action should be 
taken if ammonia leak occurred in area; include details of fans 
and means of escape. 
• COSHH assessment sheets and manufacturer safety data 
sheet for ammonia
• First aid treatment to be administered in the event of exposure
Adam Bowey - Grenco Refrigeration 
Ltd. 
CASE STUDY No 1 
• Site Layout (Chilled Cold Store)
- Large Industrial Estate, With Ammonia Plant 
Room At Rear Of Store.
- Access Road To Factory Runs Parallel To 
Ammonia Plant Room
What Happened:-
Plant room contained ammonia / glycol heat 
exchangers. A heat exchanger split leaking 
ammonia content (1,000kg) onto the plant 
room floor.
Adam Bowey - Grenco Refrigeration 
Ltd. 
CASE STUDY No 1 
(Continued)
• Refrigeration contractor was on site working on the 
refrigeration plant.
• Action / Response
The plant room was evacuated and the relevant duty 
manager notified of the incident. The internal 
employers work force were limited to work in certain 
zones of the store only.
The plant room had an exclusion zone and the access 
road was closed. It was assessed to be unsafe to 
enter the plant room due to the high concentration of 
ammonia local to the heat exchangers. A decision was 
made by the employer and the refrigeration contractor 
not to call the emergency services (Fire Brigade)
Adam Bowey - Grenco Refrigeration 
Ltd. 
CASE STUDY No 1 
(Continued)
• Conclusion
• The ammonia content in the heat 
exchanger and vessel above was left to 
leak to atmosphere before the refrigeration 
contractor was permitted to continue with 
the service repair.
• QUESTIONS / ANSWERS 
Adam Bowey - Grenco Refrigeration 
Ltd. 
CASE STUDY No 2 
• Site Layout (Frozen Food Distribution)
- Small distribution outlet, With Ammonia Plant 
Room at rear of Building and close to 
residential area (Refrigerant charge 700kg)
- Direction of leak away from residential area 
towards well established trees and residential 
road
What Happened:-
Operator error reassembling a flanged filter. 
The engineer opened the supply line to the 
filter and liquid ammonia filled the room.
Adam Bowey - Grenco Refrigeration 
Ltd. 
CASE STUDY No 2 
(Continued)
• Action / Response
The plant room was evacuated and the 
relevant duty manager notified of the incident. 
The local emergency services were called 
(Fire Brigade), who assessed residential area 
as safe
The service engineer entered the plant room 
but was unable to gain access to the filter 
housing due to the dense ammonia cloud. 
The Fire Brigade attended site and controlled 
the area until all leakage had stopped
Adam Bowey - Grenco Refrigeration 
Ltd. 
CASE STUDY No 2 
(Continued)
• Conclusion
• After initial attempt by the engineer, the 
ammonia content was left to leak to 
atmosphere (with fire brigade in 
attendance) before the refrigeration 
contractor was permitted to continue with 
the service repair.
• Damage to near by Trees 
• QUESTIONS / ANSWERS 
Adam Bowey - Grenco Refrigeration 
Ltd. 
To Stay or Not To Stay
SUMMARY
• Ammonia Emergency Evacuation 
Procedures are not optional and must 
be site specific
• Ammonia Emergency Evacuation –
Staff Training for non specialist must 
be validated
• Ammonia Procedure – Intended for 
specialist and emergency response 
staff
• Case Studies:- To stay or not to stay? –Adam Bowey - Grenco Refrigeration Ltd. 
	Ammonia Site Evacuation �
	To Stay or Not To Stay�AGENDA
	Ammonia Emergency Evacuation Procedures�
	Ammonia Emergency Evacuation Procedures
	Ammonia Emergency Evacuation Procedures
	Ammonia Emergency Evacuation Procedures
	Ammonia Emergency Evacuation Procedures
	Ammonia Emergency Evacuation Procedures
	Ammonia Emergency Evacuation Procedures
	AMMONIA EMERGENCY EVACUATION � Staff Training Validation�
	Ammonia Procedure
	Ammonia Procedure
	Ammonia Procedure
	Ammonia Procedure
	Ammonia Procedure
	Ammonia Procedure
	Ammonia Procedures
	Ammonia Procedure
	CASE STUDY No 1 
	CASE STUDY No 1 (Continued)
	CASE STUDY No 1 (Continued)
	CASE STUDY No 2 
	CASE STUDY No 2 (Continued)
	CASE STUDY No 2 (Continued)
	To Stay or Not To Stay�SUMMARY