Anhydrous Ammonia and PSM

(Presented at OSHA Update

September 19, 2014)

Simple Refrigeration System

Note: graph not created by

Susan Monroe (original source

not available)

Some Anhydrous Ammonia

Properties

Pure Ammonia, without almost no water

Gas at room temperature

Boils at -28 degree F

Efficient refrigerant

IDLH 300 ppm

PEL 50ppm 8 hr TWA

Low odor threshold 20 ppm or less

Important Industry Guidelines

IIAR Process Safety Management Guidelines

for Ammonia Refrigeration

ANSI/ASHRAE 15 (2001) Safety Standard for

Refrigeration Systems

Oil Draining Guidelines. International Institute

for Ammonia Refrigeration (IIAR), (1996).

Describes procedures for safely draining oil

from equipment.

Important Industry Guidelines

Bulletin No. 110. Guidelines for Start-Up,

Inspection, and Maintenance of Ammonia

Mechanical Refrigerating Systems. International

Institute for Ammonia Refrigeration (IIAR),

(1993, March).

Storage Vessel Design. Provides additional

information by ASME, ANSI, IIAR, and ASHRAE

about the design and installation of pressure

vessels and associated equipment

OSHA PSM Requirements

Employee Participation

Process Safety Information

Process Hazard Analysis

Standard Operating Procedures

Training

Contractors

OSHA PSM Requirements

Pre-start up review

Mechanical Integrity

Hot Work Permits

Management of Change

Preventive Maintenance

Emergency Response

Audits

Common Myths vs Reality

Outside leaks are not a problem because they will blow upwards away from employees evacuating (actually sometimes the cloud descends directly onto evacuating employees)

Ammonia warning properties are good; you will not stay around to be overexposed, so no need to worry about permanent lung injuries or fatalities (evacuation problems are common, and people get trapped even outside the plant after evacuating, plus, even in upper lungs, it is caustic)

Six Anhydrous Ammonia

Fatalities in One Year

May 14, 2009: American Cold Storage,

Louisville, KY 2 fatalities

June 20, 2009: Mountaire Farms, Lumber

Bridge, NC 1 fatality

July 15, 2009: Tanner Industries,

Swansea, SC ? fatality

November 16, 2009: CF Industries,

Rosemount, MN 2 fatalities

Example Problems in

Refrigeration w/ Anhydrous

Ammonia Standard wiring or ventilation in the

engine room (not designed for flammable environment)

NH3 leaks out of its pressurized system

Catastrophic leaks due to not locking out during maintenance, not opening stop valves after maintenance, or striking a component (one example---forklift w/ raised prongs crashes into overhead evaporator)

Explosions

Safety Culture Problems in Facilities Using Anhydrous Ammonia (Subjective Observations, Not OSHA Policy Statement)

Some mechanics and maintenance personnel not completely accepting new Process Safety Management regulations

PSM Engineers sometimes younger, less authority, sometimes more formal education, reporting to Safety Manager, not fully integrated with operators and mechanics, who report to Maintenance Manager

PSM Engineers challenged with older systems which have enlarged over time and paperwork is missing/outdated/hard to obtain sometimes due to culture gap

Other Safety Factors/Problems

in Ammonia Refrigeration plant Shift work is hard on the human body, usually

12 hours, often rotating shifts, leads to poor sleep, inattentiveness

Mechanics on-call at night, awoken from sleeping, have to drive to plant and take care of a hazardous situation when they just woke up

Refrigerated plants are cold, can add to stress of being awoken in the night, going from warm bed to freezing areas

None of this is regulated; unlikely to change

Typical citations:

No or inadequate emergency evacuation plan

Examples:

Pig slaughter operation added on many rooms over time, could not hear alarms in some added rooms

No one knows the alarm signal

Employees do not know that they are supposed to evacuate (non-English speaking)

Typical Citations:

Employees not trained to pull alarms/ not empowered to look for hazards

No ammonia monitors where it is likely to leak

No practice drills or contact with local emergency entities or private spill response teamsoften no outside entity knows

Not replacing valves per industry standards (ex: pop-ups every five years)

Operators not trained on PSM

Typical Citations:

Operators not trained to wear SCBA when approaching, for example, the king valve to turn it off during an emergency

SCBAs located in the engine room (where the leak is likely to occur)

No wind socks to determine which direction to evacuate

Management or employees not aware of wind sock purpose or how to use that information

Typical Citations

Engine rooms not having proper electrical classification wiring (very common)

Engine rooms not having proper emergency ventilation systems (or vent calculations missing)

For older systems, original P and IDs are missing or still being used with no updates even though inventory has increased tens of thousands of pounds

Typical Citations

Relief calculations not available

Relief not re-calculated after system increases or changes

Management of change overlooked:

Valves not replacement in kind

Gasket material changes during replacement

Lack of documentation of MOC

Everything being MOC, even replacement in kind (usually MOC in this case is all approved by one person)

Checklist Items

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Checklist Items

Goodyear Tire Company

Houston 2008

Con Agra 2009

Con Agra 2009