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.