IIAR

BY KEM RUSSELL

Coordination with local responders is a basic safety responsibility for any facility, but in some cases, even if a company has a well-articulated emergency plan, the lessons learned from a small incident can reveal much bigger considerations.

In this column, in each issue of the Condenser, we look at lessons learned from many different kinds of situations. Below, we examine a small release, including what causes contributed to the incident, how a response effort was handled and what can be learned about emergency planning by observing how a facility addressed communication with first responders in the midst of the event.

In the following paragraphs, we’ll lay out the events leading up to and following a release, and examine the lessons learned at each stage of the response.

It was a nice evening late in the summer, and the ammonia system for a large cold storage facility had been shut down after all of the stored product had been packed and shipped.

The computer control system for the refrigeration system remained operational, primarily for the ammonia detection system that was kept active around the clock to monitor and alarm.

This facility, like many similar facilities, had many pressure vessels designed for 150 psig as the maximum working pressure. This maximum vessel working pressure was usually acceptable, since system operating suction pressure rarely reached 90 psig.

The facility had not had a complete system shutdown during the summer for several years, so although the shutdown was done as described in the standard operating procedures, an important precaution had not been considered in the shutdown procedure.

That important precaution serves as the first “lesson learned” from this scenario: when a system is completely shut-down the system pressure will begin to equalize at a pressure corresponding to the ambient temperature.

In this particular case the ambient temperature was around 75°F to 80°F. Checking the temperature pressure chart for anhydrous ammonia will reveal a corresponding pressure of 125.5 psig to 138.0 psig. The upper range of this pressure is getting into an area of concern with a 150 psig relief valve. The concern comes with regard to the possibility that a relief valve may start weeping or simply release. In this particular case, one of the 150 psig relief valves did release.

The release began at about 10 pm, and since the facility was shut down, there were no facility personnel on-site.

The alert that a problem was developing came from a person who lived close to the facility site. The person was the first one to realize something unusual was occurring, because of the very loud noise they heard coming from the facility.

The person did not have any phone numbers for facility contacts, so they called 911. The emergency responders, in turn, did not have an established protocol for communicating with facility personnel, a factor that serves as the basis of the remaining “lessons learned” in this scenario.

Second lesson learned: establish a facility contact protocol with local emergency responders.

The fire department, which was located about two miles down a main road, responded to the site in just a few minutes. It just so happened that when the call went out from the fire dispatch, one of the facility personnel who also served as a volunteer fireman heard the call on his fi re dispatch radio and quickly notified fire dispatch that he was en-route to the facility.

It would have been a considerable time before any facility personnel would have been notified if this person hadn’t had an active fire radio. The fire dispatch would have had to search for a name and phone number of a facility person to call.

With the help of the facility employee, and after a quick investigation, it was determined that a relief valve was releasing from a surge drum vessel that was located outside and approximately 25 feet in the air.

Realizing that they were dealing with an ammonia release, the fire department on-scene commander asked for assistance from the local police department to close the roads near the release point. The state patrol was also notified because it was a hazardous material release.

Because the responding fire department was not trained to offensively deal with ammonia releases, they called for assistance from a neighboring community that did have an allhazard response team. Even though the facility was part of the County Emergency Plan, the duration of the release was extended because there was no one with the knowledge, training, or equipment to “offensively” work on the problem.

The response in this case highlights the third lesson learned from this incident: make sure local responders are trained in the process of determining what resources are needed to deal with an ammonia release during its very early stages.

With no one, including the fire department personnel or the facility employee trained, or with the proper personal protective equipment to do a closer investigation, the leak continued.

In addition, there was no person on-site who was knowledgeable and experienced in ammonia refrigeration system operation, a fourth lesson learned: designate a person who can be immediately available to assist responders in considering a plan of action.

In this case, the next option was to contact one of the local refrigeration contractors for assistance.

In a short time a refrigeration technician representative from a refrigeration contractor arrived, but that person was also restricted from getting near the release point since they also did not have the training or personal protective equipment to approach the ammonia release.

However, after a short review of the operating pressures of the system, it was suggested by the technician that starting the system and lowering the suction pressure might have a desirable effect. Within a few minutes of starting the system, the suction pressure greatly reduced, dropping quickly below 100 psig, and causing the relief valve to re-seat, stopping the release.

The release duration was approximately two-and-a-half hours, during which time the relief valve never closed.

Although the release lasted twoand-a-half hours the incident itself was shut down relatively quickly thanks to some quick thinking and a quick response, but some of the main lessons learned by this incident should not be ignored.

First, all potential shutdown conditions should always be thoroughly examined, and procedures should be developed to keep system pressures below relief valve release points even during shutdown conditions. In addition, facility emergency plans should address the communication to and from neighbors in the event that an incident occurs.

Second, facilities should make sure that local responders have facility contact information readily available for key facility personnel, and that the facility has coordinated and worked with the local responders on a regular basis. In addition, that coordination should include all work shifts that the responders might have.

Third, if a facility plans to rely on local responders, and those responders are not trained for a hazmat response, the facility should decide ahead of time what safe and “defensive” actions it plans to take to reduce or stop a release in a shorter period of time.

Finally, facilities should be prepared to provide experts knowledgeable in the operation of an industrial ammonia refrigeration facility, and make plans for them to be quickly contacted if the facility refrigeration personnel are not readily available.