SAFETY AND SUSTAINABILITY
A new standard of safety
for onshore passive fire protection
R. HOLLIDAY, PPG Protective and Marine Coatings, Aberdeen, Scotland
The onshore energy and petrochemicals sector is defined by the strength of its
safety culture, but it has only recently begun moving toward adoption of the highest fire protection standards. For many
years, industry practice has been to protect onshore assets primarily against pool
fires, but recently the industry has begun
to recognize the need to adopt standards
covering the more dangerous hazards of
jet fires. This is particularly important in
light of the huge increase in gas processing, transport and handling, whether
from U.S. shale gas extraction, growth in
LNG or other sources, such as hydrogen.
Gas processing facilities and shipping
terminals are threatened by some of the
biggest potential hazards in terms of leaks
and spills, with the associated risks of
cryogenic spills, explosions and jet fires
(FIG. 1). The expansion of gas import and
export capacity creates hazards different
from those in refineries or petrochemical
plants. To adequately protect these plants,
designers and operators must consider
protection from jet fires at a design level.
This is an issue of concern for the U.S.
natural gas industry, since the American
Petroleum Institute (API) 2218 standard
on fire safety is designed to cover fireproofing at petroleum refineries and petrochemical processing plants, rather than
LNG terminals and gas processing facilities. The potential risks are far greater at gas
export terminals because much more processing takes place before the natural gas
can be turned into a liquid for shipment.
The process to remove contaminants and
process the gas to the required purity level
involves a sequence of treatments at high
pressure, bringing more complexity to the
plant design and increasing the potential
for leaks from multiple sources.
Emerging standards. The requirement
for a standard against jet fires came to
the public’s attention after the Piper Al-
FIG. 1. Multi-directional jet fire release from leaking flange joint. Photo courtesy of DNV GL.
pha disaster in the North Sea in 1988, in
which 165 people on the platform and
another two from the rescue boats lost
their lives. One of the key findings of the
subsequent enquiry was that the passive
fire protection (commonly referred to as
fireproofing) in place on the platform did
not survive as long as predicted. In fact,
the jet fire on Piper Alpha destroyed the
fire protection materials within a matter
of minutes, rather than the 1 hr–2 hr for
which most systems are designed. For the
offshore industry, it was a wakeup call.
Much subsequent research was carried out on the behavior of jet fires; however, such testing is expensive. In the early
1990s, work started on a more economical
and repeatable test that could become a
standard for testing of passive fire protection materials. The resulting standard—
ISO 22899-1—became an internationally
recognized benchmark that could be used
to test the ability of fireproofing to withstand jet fire (FIG. 2). It is still the only recognized standard of its type.
For many years, the onshore industry
paid much less attention to jet fires than to
pool fires, despite the fact that these types
of fires can happen anywhere onshore or
offshore, and the result is a credible fire
scenario that should be mitigated against.
Fire protection in the onshore market
has largely been driven by the API 2218
standard, which did not address jet fires
until an incident at Valero’s McKee, Texas
refinery in February 2007. A fire escalated
significantly because jet fires were much
more far-reaching than the pool fires for
which the facility’s fire protection was designed. Again, fireproofing was installed,
but in the wrong place and to the wrong
performance standard.
The main body of API 2218 is applicable only to pool fires, but the revised standard now includes an annex stating that
asset owners should consider jet fires in
the design of their fireproofing. The guidance covers fireproofing of fittings and
steel components, but direct guidance on
non-pool fires at gas storage and processing facilities is outside of its main scope.
Industry trends. Even at a time when
the industry was recognizing that hazards
Gas Processing & LNG | NOVEMBER/DECEMBER 202013
SAFETY AND SUSTAINABILITY
were becoming more severe, many passive fire protection (PFP) manufacturers
were designing coatings for less severe
fires because jet fire resistance standards
did not exist in any meaningful way.
These pool fire-resistant materials are
already in use on the U.S. LNG export facilities currently in operation, but when
the potential risks are considered in detail, these coatings do not accurately address the hazards present at these facilities. A gas facility will have a low risk of
pool fire but a very high risk of jet fire.
However, some designers will still specify coatings designed only for pool fires
because they are less costly than those
designed to resist jet fires.
It is important to note that the intensity and high momentum of jet fires
means that water deluge is not effective
as a means of active fire protection. The
jet will punch straight through water and
will heat up the steel, vessel and piping
very quickly, to the point where rupture
and resulting boiling liquid expanding vapor explosion (BLEVE) is a real risk.
Another problem is that deluge may
extinguish the fire without stopping the
leak, which can result in clouds of gas that
can then ignite and cause an explosion
that is potentially more lethal than the jet
fire, risking damage to active fireproofing
or passive fire protection if it is not resistant to explosion.
No compulsion exists for fireproofing
manufacturers to design against the most
hazardous potential event; designing
against jet fires is certainly more complicated (and potentially more costly) than
designing for pool fires alone.
High-performance fireproofing coatings, including the newest coatinga on the
market, have a minimum of 30 min of jet
fire resistance. This ties into the API standard 520-1, which recommends that an
operator should be able to depressurize
the plant quickly enough to halve working pressure in 15 min.
Designing a good jet fire system requires a highly robust char, which is an
open and lightweight structure for optimal insulation. New coatings feature
effective insulating char at a lower thickness than pool fire-only products, but
still provide good jet fire resistance. The
use of very-high-temperature-resistant
carbon fiber mesh extends the jet fire resistance to 4 hr while keeping the thickness and weight of the system very low.
Jet fire first. The latest stage in the jet
FIG. 2. Medium-scale jet fire test to ISO
22899-1. Photo courtesy of PPG Industries.
FIG. 3. Large-scale jet fire test at the
Spadaedam research facility in northern
England. Photo courtesy of DNV GL.
14NOVEMBER/DECEMBER 2020
fire testing process saw Underwriters
Laboratories (UL), which underwrites
safety standards at U.S. onshore chemical
and energy plants, agree to adopt the ISO
22899 standard for jet fire testing. The
process of testing for jet fires has undergone a significant evolution from simple
observations providing a basic recognition to a minimum of three samples of
each type of certification sought.
The test standard includes different
configurations for structural steel, piping,
walls, decks and bulkheads, each requiring a series of tests. When preparation of
test specimens, witnessing of the test, assessment and certification are included,
the per-test cost can reach $50,000. The
process requires a large investment for
proper completion, making certification
a serious commitment (FIG. 3).
| GasProcessingNews.com
A new way forward. The developments
in safety that have taken place in the offshore industry over decades have demonstrated how standards can help effectively
manage risk, but this must happen more
and faster in the onshore market.
The energy industry sometimes
moves slowly in adopting new or best
practices, but development of new standards and recognition by U.S. agencies of
international standards for resistance to
jet fires is an encouraging step forward.
The fact there have been, until recently,
no published guidelines for jet fire resistance is not a justifiable defense when it
comes to protecting people and assets to
the highest degree possible.
LNG demand is expected to remain
firm as it takes an increasing share of the
energy mix in the future, and gas is also
required as a feedstock for chemical and
petrochemical plants—demand that will
lead to growth in total market size.
As more facilities seek final investment decision and project greenlight, the
natural gas industry must move faster to
address the risks arising from complex
fires. It would be unfortunate for a major
incident to highlight this potential weakness in safety standards just as cleaner energy sources are needed.
Even in the post-COVID-19 environment, where project budgets are likely to
be under pressure, there is a clear argument for using fire-resistant coatings that
go beyond the minimum safety requirements. It is not a question of trading off
price for safety, since such coatings can
help make these critical facilities inherently safer. GP
a
NOTES
The PPG PITT-CHAR NX coating, which is certified to UL’s ISO 22899 standard
RICHARD HOLLIDAY is Global
Director of Hydrocarbon PFP
at PPG Protective and Marine
Coatings, based in Aberdeen,
Scotland. He is a recognized
technical authority and subject
matter expert in the fields of
passive fire protection (PFP), thermal insulation,
heat shielding and protective coatings. He has held
senior technical and business development roles with
manufacturers, engineering contractors and technical
safety consultants for large corporations and smallto-medium enterprises. Mr. Holliday is a Mechanical
Engineer by training with post-graduate qualifications
in management and information systems and 35 yr
of experience in the design, testing, specification,
application and inspection of PFP systems,
both onshore and offshore, on a global basis.