This photogrph was taken during the T2 Laboratories response by District Chief Steve Gerbert of the Jacksonville Fire-Rescue Department.

Better PSM Metrics

The BP US Refineries Independent Safety Review Panel (“Baker Panel”) and the U.S. Chemical Safety and Hazard Investigation Board both recommended improved industry-wide process safety metrics in their final reports dealing with the 2005 explosion at the BP Texas City, Texas, refinery. This has also been a subject of frequent discussions among process safety organizations such as the Center for Chemical Process Safety (CCPS), as well as magazine articles and other forums.

Individual companies and some trade associations had defined metrics, but a standardized set of metrics used by the majority of companies and trade associations had not been implemented. In 2006, CCPS formed a committee to publish a guideline defining uniform metrics that could serve as a global standard. That committee has recently published recommendations for leading and lagging metrics of PSM performance at www.aiche.org/ccps/ metrics/index.aspx.

This article summarizes the recommendations and explains the utility of the metrics to better manage PSM. The ultimate objective of this committee is to complete a guideline book originally authorized by CCPS, so that additional information and guidance is available to individual companies on how to better use metrics to improve their process safety performance. The recently published document is intended to propose an industry-wide lagging metric and suggested leading and other metrics for individual companies’ consideration. The development of these industry-wide recommendations was led by CCPS in cooperation with numerous international chemical and petroleum trade associations, regulatory agencies, and other stakeholder organization

DEC. 19, 2007, 1:30 P.M. EST: RESPONSE TO THE T2 EXPLOSION Jacksonville’s hazmat teams sometimes use the CAMEO database to find out what chemicals a facility uses, but not this time.

by Jerry Laws

This year began with an investigation already under way into a reactive chemical explosion that had killed four workers at the T2 Laboratories Inc. plant in Jacksonville, Fla., on Dec. 19, 2007, and was captured by a U.S. Coast Guard surveillance camera monitoring the Jacksonville port.

The video shows one of the most powerful explosions ever examined by the U.S. Chemical Safety and Hazard Investigation Board, Investigator-in-Charge Robert Hall said during a Jan. 3 briefing. Injuries requiring medical attention occurred as far as 750 feet from the batch reactor that blew up, while large pieces of the reactor’s top were found about one quarter-mile away. It took a pressure of several thousand pounds per square inch to rupture the reactor, which had steel walls 3 inches thick, he said.

Lt. Todd Smith, a shift commander of the Jacksonville Fire-Rescue Department’s North side hazmat team, said 17 hazmat personnel from the city’s two teams responded. His team reached the plant about 30 minutes after the explosion, with the initial caller reporting it as a transformer fire. (Two electrical generating stations are near the T2 site, and the blast downed large electrical cables that lay in the street when District Chief Steve Gerbert arrived. Gerbert, who lives nearby, was off duty but went to the scene and photographed the response.)

Smith said several container trucks, processing units, and storage tanks were afire and exploding when his team arrived. An engine company had parked near the front of the plant when they arrived, so the hazmat unit pulled up beside them. No firefighters had entered the plant’s fenced area at that time, but there were reports people were trapped inside, Smith said. “The amount of damage we could see to all the parked cars, all the buildings in that area, was tremendous. It was obvious there was a major explosion that had taken place. There was a lot of fire and a lot of smoke, several explosions.”

An injured worker had told one of Smith’s team members about some of the chemicals inside. The hazmat team entered the plant under the protection of two 2.5-inch hose lines to see what was involved. They confirmed that two intense, pressure-type fires visible in the rear of the plant were two tube trailers of carbon monoxide that were venting and burning. They put together a foam operation for the flammable liquid fire, and the pressure fires burned out on their own, Smith said.

He said the hazmat teams frequently rely on CAMEO, a chemical database created for first responders by EPA and NOAA, for information about the chemicals used at a facility where they’re heading on an emergency call. They did not use CAMEO in this case, which happened on a fairly warm afternoon, when the smoke column fortunately moved away from the firefighters, Smith said. The team conducted air monitoring upwind and downwind, using five gas meters with PID lamps, an FID/PID organic vapor monitor, and colorimetric tubes for hydrocarbons. They established a hot zone that encompassed the entire fence line of the plant and was backed out 500 to 1,000 feet farther at one point, then moved closer when air monitoring indicated the air was clean, he said.

The blast caused 33 injuries, with many of the injuries caused by flying or falling debris from structural damage to off-site buildings, the Chemical Safety Board reported Jan. 25. No firefighters were hurt. The board said its investigators’ preliminary findings were that T2 personnel lost control of a process used to produce a gasoline additive, methylcyclopentadienyl manganese tricarbonyl, during the first step of the process, when more than 1,000 pounds of metallic sodium was reacted with other raw materials, producing hydrogen gas as a byproduct.

For information about CAMEO, visit http:// epa.gov/OEM/content/cameo/what.htm.

CCPS was established in 1985 by the American Institute of Chemical Engineers (AIChE) for the purpose of helping industry avoid or mitigate catastrophic chemical accidents. More than 100 corporate members around the world drive the activities of CCPS, which strongly recommends that companies around the globe adopt and implement these recommendations.

The Need for Metrics
Essential elements of any management system are a set of guiding measures to assist in shaping appropriate performance and a process against which you can measure performance. Therefore, to continuously improve process safety performance, it is essential that companies in the process industries implement effective management controls, including the adoption of leading and lagging process safety metrics. The key performance indicators and associated metrics should reflect the goals of the organization and indicate exemplary performance.

The CCPS document describes three types of metrics:

1. “Lagging” metrics: a retrospective set of metrics that are based on incidents that meet the threshold of severity that should be reported as part of the industrywide process safety metric.

2. “Leading” metrics: a forwardlooking set of metrics that indicate the performance of the key work processes, operating discipline, and/or layers of protection that prevent incidents.

3. “Near miss” and other internal lagging metrics: describing less-severe incidents (i.e., below the threshold for inclusion in the industry lagging metric) or unsafe conditions that activated one or more layers of protection. Although these events are actual events (i.e., a “lagging” metric), they are generally considered to be a good indicator of conditions that could ultimately lead to a severe incident.

Lagging Metrics
The CCPS document describes a set of definitions and metrics recommended as industry-wide lagging metrics. Lagging metrics allow for a company to determine trends and performance against pre-determined goals. While retrospective, they are valuable in allowing management to understand issues during their incipient stage, in the case of lagging metrics oriented toward smaller process safety incidents or near misses.

While companies may adopt a wide range of metrics oriented toward lesser incidents and benefit from documenting them, CCPS wanted to recommend a standard level of incidents, at a minimum, that balanced the benefits of standardized data collection while minimizing the burden on the whole of industry for the effort involved.

Process Safety Incident (PSI)
Essential to lagging metrics was the need for CCPS to define a process safety incident. This was possibly one of the more important aspects of the project, where strong collaboration between CCPS committee members, representatives from many trade associations, and external stakeholders was essential. For the purposes of the common industry-wide process safety lagging metrics, an incident is reported as a process safety incident if it meets all four of these criteria:

• Chemical or chemical process involvement
• Above minimum reporting threshold
• Location
• Acute release

Chemical or chemical process involvement
For an incident to satisfy the chemical or chemical process involvement criterion, a chemical or chemical process must have been directly involved in the damage caused. For this purpose, the term “process” is used broadly to include the equipment and technology needed for petrochemical production, including reactors, tanks, piping, boilers, cooling towers, refrigeration systems, etc. An incident with no direct chemical or process involvement (e.g., an office building fire, even if the office building is on a plant site) is not reportable.

An employee injury that occurs at a process location, but in which the process plays no direct part, is not reportable as a PSI (though it could be an OSHA reportable injury or another agency’s reportable injury).

Reporting thresholds
A release of material or energy from a chemical process qualifies as a threshold if it results in any of the three situations below:

1. An employee or contractor lost-time injury and/or fatality, or hospital admission and/or fatality of a third party (nonemployees/ contractor);

2. Fires or explosions resulting in $25,000 or more of direct cost to the company; or

3. An acute release of flammable, combustible, or toxic chemicals from the primary containment (i.e., vessel or pipe) greater than the chemical release threshold quantities described in Table 1 of the CCPS guidance (which includes hazardous material releases ranging from 5 to 2,000 kg, depending on hazard class), excluding releases to a properly designed and operating control device specifically designed for that event (e.g., flare, scrubber, or relief devices per API Standard 521 or equivalent).

For the purposes of applying these threshold values for “Flammable Gases/Vapors,” “Flammable Liquids,” and “Combustible Liquids,” the user may use either the definitions commonly used within the petroleum refining industry (based upon National Fire Protection Association, NFPA-30, definitions), the UN Dangerous Goods (Class 2, Div. 2.1 and Class 3), or the Harmonized System of Classification and Labeling of Chemicals (GHS), Chapters 2.2 and 2.6. These different methods classify materials in a similar manner; therefore, most flammable materials will fall into the same category regardless of the definitions used. Further information is provided in the CCPS document.

Lost-time injuries and fatality incidents
Lost-time injuries and fatality incidents that occur as a result of process-related loss of primary containment, fire, or explosion are those that fit into one of the following categories:
• Employee (lost time and/or fatality)
• Contractor and subcontractor (lost time and/or fatality)
• Third party (injury/illness resulting in hospital admission or fatality)

Location
Incident criteria were developed to limit the scope of the incidents documented from a physical location standpoint. An incident satisfies the location criteria if the incident occurs in production, distribution, storage, utilities, or pilot plants of a facility reporting metrics under these definitions. This includes tank farms, ancillary support areas (e.g., boiler houses and wastewater treatment plants), and distribution piping under control of the site.

All reportable incidents occurring at a location will be reported by the company that is responsible for operating that location. This applies to incidents that may occur in contractor work areas, as well as other incidents. At multi-party sites, the company that operates the unit where the incident initiated should record the incident and count it in its PSI metric.

Acute release
CCPS wanted to limit the events documented to a consistent criterion for time of the release. A “1-hour” rule applies for the purpose of the reporting under this metric—i.e., the release of material reaches or exceeds the reporting threshold in one hour or less. If a release does not exceed the TQ level over any one-hour period, it would not be treated as a PSI.

Process Safety Incident Severity
CCPS developed severity-level definitions for each consequence category for each process safety incident. This allows for a gradation of incident severity against standardized definitions. The criteria illustrate the comprehensive nature of the considerations for process safety incident consequences, with four levels ranging from minor to major and from issues including loss of reputation to loss of life.

The categories of incident consequences are safety/human health, fire or explosion (including overpressure), potential chemical impact, and community/ environment impact.

Rate Adjusted Metrics
Utilizing the definitions described above, a variety of rate-based metrics can be generated. These include:

A. Process Safety Total Incident Rate (PSTIR):

PSTIR =     Total PS incidents x 200,000                   
                  Total employee & contractor work hours

B. Process Safety Incident Severity Rate (PSISR) (i.e., severity-weighted process safety incident rate formula):

PSISR =    Total severity score for all PS incidents x 200,000
                  Total employee, contractor & subcontractor work hours

In determining this rate, 1 point is assigned for each Level 4 incident attribute, 3 points for each Level 3 attribute, 9 points for each Level 2 attribute, and 27 points for each Level 1 attribute, as shown in Figure 1. Theoretically, a PSI could be assigned a minimum of 1 point (i.e., the incident meets the attributes of a Level 4 incident in only one category) or a maximum of 108 points (i.e., the incident meets the attributes of a Level 1 incident in each of the four categories).

Leading Metrics
CCPS also published a number of potential leading metrics. If measured and monitored, data collected for leading metrics can give an early indication of deterioration in the effectiveness of these key safety systems and enable remedial action to be undertaken to restore the effectiveness of these key barriers before any loss-of-containment event takes place.

The safety systems for which leading metrics have been developed are:

• Maintenance of mechanical integrity;

• Action items follow-up;

• Management of change; and

• Process safety training and competency (and training competency assessment).

It is recommended that all companies adopt and implement leading process safety metrics around those four categories, plus “safety culture.” However, given the number of metrics defined, it may be impracticable to collect and report data for each category described in the CCPS document. Companies should identify which of these components are most important for ensuring the safety of their facilities and should select the most meaningful leading metrics from the examples provided. Other company-specific leading metrics may be defined, as well, if applicable.

These leading metrics recommendations will continue to be refined as the CCPS Metric Committee finalizes the Metric Guideline book in 2008. Enhancements or suggestions to these metrics are welcome.

References
1. CCPS, “Process Safety Leading and Lagging Metrics,” AIChE, New York, 2007.

This article originally appeared in the April 2008 issue of Occupational Health & Safety.

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