Trends and activities in globalization, technology, regulation, environmental and community stewardship, and industry consolidation have dramatically affected the cold storage industry in the last decade. What’s more, there is little to no evidence that changes effected by these elements are going to subside.

At the same time, most cold storage facilities in North America rely heavily on ammonia refrigerant to keep product cold. To meet storage demands and in light of industry consolidation, both facilities and refrigeration systems grew in size. As a matter of fact, the decrease in the number of facilities 500,000 ft2 or less has only led to a decrease in total volume (attributable to those facilities) of about 25,000,000 ft2. Concurrently, an increase in facilities larger than 5,000,000 ft2 has led to an increase in total volume (attributable to those facilities) of more than 800,000,000 ft2.  Now, under the microscope of three separate federal agencies, there is increasing pressure to reduce the charge of ammonia in refrigeration systems.

EPA, OSHA and DHS: The Regulatory Climate

Three agencies are enacting regulations that affect industrial cold storage facilities using ammonia refrigeration. They are the U.S. Environmental Protection Agency (EPA), U.S. Occupational Safety and Health Administration (OSHA) and U.S. Department of Homeland Security (DHS).

EPA. EPA’s role is the result of three different charters:

  • Chemical Accident Prevention — Risk Management Program (RMP). Developed under Section 112 of the Clean Air Act, this program has resulted in the development of the Chemical Accident Prevention regulations, which include ammonia when the quantity exceeds the 10,000-pounds threshold (also known as the TQ, or threshold quantity).
  • Superfund Amendments and Reauthorization Act (SARA) Title III, Community Right-to-Know — Chemical Inventory Reports. This act establishes requirements for federal, state and local governments and industry regarding emergency planning and reporting on hazardous and toxic chemicals. In addition, it issues a requirement for all facilities that hold an ammonia inventory of 500 pounds or more to file a Tier 1 or Tier 2 report on an annual basis.
  • Emergency Release Notifications. Two different federal acts drive emergency response notification requirements. They are the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA or Superfund), and the Emergency Planning and Community Right-to-Know Act (EPCRA). For industrial cold storage facilities covered under these regulations, the threshold for an ammonia release — the Reportable Quantity (RQ) — is 100 pounds in a 24-hour period. Any release reaching or exceeding this threshold must be reported within one hour of the release.

OSHA. While fines assessed under various EPA violations have likely been the most severe, OSHA rules and violations typically have been the most visible throughout the industry.

The rule most familiar to those facilities exceeding the 10,000-pounds threshold is that of the process safety management (PSM) program. There are 13 critical components to this rule. It should be noted, however, that even facilities that do not fall under the auspices of PSM are still expected to adhere to the basic tenets of Recognized and Generally Accepted Good Engineering Practice (RAGAGEP).

DHS. This federal entity has been directed to identify, assess and ensure effective security at high risk chemical facilities throughout the country. A program has been instituted under the Chemical Facility Anti-Terrorism Standards (CFATS) rule to assess certain chemical facilities required to register with DHS and conduct security vulnerability assessments using DHS standards. While it is unlikely that few, if any, cold storage facilities will fall under this particular rule, it is well within the realm of possibility. As with the EPA and OSHA PSM programs, the screen threshold quantity (STQ) of ammonia under CFATS is set at 10,000 pounds; however, the method of calculation is different and more encompassing.

Other Regulatory Bodies. At the state level, it also is worth noting that California — through its California Accidental Release Prevention (CALARP) program — is unique and influential in the regulatory landscape for several reasons: 

  • The state threshold quantity (TQ) for anhydrous ammonia is 500 pounds — a much more stringent regulation compared to 10,000 pounds threshold at the federal level.
  • CALARP facilities are required to be inspected by an administrative agency once every three years in order to prove compliance with the facility’s risk management program.
  • An updated RMP must be submitted to the administrative agency at least once every five years.
  • The facility must perform a compliance audit at least once every five years to verify that the RMP is still valid and no new processes have been added.

It is clear now that the trends impacting the industry over the last several decades have evoked federal oversight and state mandates.

Ammonia and the Importance of Reducing Charge

Although ammonia has been — and continues to be — the predominant refrigerant used in the cold storage and food processing industry, its use has come under increased scrutiny in recent years as a result of industrial accidents, the potential as a terrorist target, drug trafficking and growing local concerns.

From a purely technical and environmental perspective, the benefits of ammonia as a refrigerant are unparalleled:

  • It is a natural refrigerant with no global warming or ozone-depletion potential.
  • Its heat transfer characteristics are among the best substances known to man.
  • It is inexpensive.
  • Its use for more than 100 years has led to a base of experience unlike any other refrigerant in the industry.

However, in the hands of untrained or careless individuals or in poorly maintained facilities, ammonia can be a highly dangerous chemical.

Because of this, the actual size of the ammonia charge in any given facility has come under a large and expansive examination by regulatory authorities, communities and insurance providers.

Over the past decade, a number of public refrigerated warehouse (PRW) owners have recognized the need to take action in reducing the ammonia system charge in their facilities. This recognition has broadened over the past few years, and the PRW community has reached out to engineers, contractors and equipment suppliers to find innovative ways to minimize their ammonia system charges.

As a result, reducing ammonia charge is being done through one of four approaches:

  • Eliminating all but the most essential ammonia charge.
  • Maximizing the heat transfer from the ammonia residing within the system to the air or secondary fluid.
  • Substituting other heat transfer fluids for ammonia wherever practical and economically viable.
  • Rejecting the more-is-better philosophy on refrigeration when it comes to ammonia charge.

What has taken place over the past five years has been truly remarkable. The industry has embraced the need for change and has shown a true willingness to discard the seemingly age-old paradigms about refrigeration system design. Which of the approaches now being used to limit ammonia charge is best — or will be the “winner” five years from now — is yet to be known. What is known is that there is no one-size-fits-all answer. Different approaches work best in different systems, depending on the size, type and business model of the facility in question. PC

 

Editor's Note: This article is based on a white paper developed under the International Association of Refrigerated Warehouses (IARW) and the International Association for Cold Storage Construction (IACSC) Refrigeration & Energy Committee. For information about IARW or IACSC, call 703-373-4300. To read the full whitepaper, please visit http://bit.ly/AmmoniaPaper.

Please look for Part 2 of this article, which will focus on system types, in the May 2016 issue of Process Cooling.