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 teams—often 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