Hazard Study Process Glossary

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Process Safety Guide:
GBHE-PSG-HST-090
Hazard Study Process
Glossary
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Information contained in this publication or as otherwise supplied to Users is
believed to be accurate and correct at time of going to press, and is given in
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for its own particular purpose. GBHE gives no warranty as to the fitness of this
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(statutory or otherwise) is excluded except to the extent that exclusion is
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information. Freedom under Patent, Copyright and Designs cannot be assumed.

Process Safety Guide: Hazard Study Process: Glossary
PURPOSE
This document provides a glossary of defined roles and terms used in the
hazard study process.
ACS – Advanced Control Systems
High level process control using predictive models to anticipate the
process behavior.
AIChE - American Institute of Chemical Engineers
ANSI – American National Standards Institute
AQS – Air Quality Standard
A concentration of a substance in air deemed to be acceptable to the
environment being considered. The AQS may apply at local, national or
international level.
Atmospheric Pressure Storage Tank
A container or structural envelope subject primarily to hydrostatic
pressure. In Europe tanks with gas at low pressure, typically less than 0.1
bar above the liquid, are included in this definition. In North America tanks
with internal pressure of up to 15 psi g. are covered in this description.
BPCS – Basic Process Control System
A system that responds to input signals from the process, its associated
equipment, and/or an operator and generates output signals causing the
process and its associated equipment to operate in the desired manner.
BPEO – Best Practical Environmental Option
Best option when all aspects, including practicality, secondary and indirect
environmental effects such as abatement costs, have been taken into
consideration.

Basis for Safe Operation
The basis for safe operation should make clear why the design is safe to
operate. For example, explosions may be avoided by preventing
flammable mixtures, by control and/or trip systems, eliminating, as far as
possible, ignition sources, providing explosion relief or designing to
contain explosions. (Also known as Basis of Safety.)
Bund
A containment area in which one or more storage tanks, vessels or other
equipment are located comprising leak tight floor and walls. (Known as a
dike in North America.)
CCPS - Center for Chemical Process Safety
Run by the AIChE, of which ICI is a member.
C/E - Control/Electrical
Refers to the joint specialization covering issues related to process control
and electrical equipment and supply.
CIMAH - Control of Industrial Major Accident Hazard Regulations (UK)
Superseded by COMAH.
COMAH - Control of Major Accident Hazards (UK)
Regulations enacted as a consequence of the EEC “Seveso Directive”
82/501/EEC.
COSHH - Control of Substances Hazardous to Health Regulations (UK)
Capital Projects
The means whereby fixed assets are designed purchased, built, extended,
modified, subject to special repair and maintenance or demolished.

Note: The GEPs apply to all Capital Projects:
• Whether the work is financed from Capital or Revenue budgets;
• includes those controlled by local sites or facilities
• includes Capital Equipment such as Transport Containers for Dangerous
Goods.
Checklist
A method for hazard identification by comparison with experience in the
form of a list of failure modes and hazardous situations.
Chemical Hazard Assessment
Experimental assessment of the chances and kinetics of a runaway
reaction or detonation using specialist laboratory techniques such as
Differential Thermal Analysis, Accelerating Rate Calorimetry, or Dewar
Flask. This work is often essential for sizing reliefs of reactors in which
exothermic reactions are carried out. The use of an outside specialist
contractor will probably be required.
Commissioning Manager
A person appointed by the Project Manager or Operating Manager to carry
out defined responsibilities (relating to the achievement of beneficial
production of a modification, expansion or new plant).
Controlled Equipment
Equipment that should be given special attention because of legislative or
company SHE reasons for purposes of ensuring integrity.
Criterion
A standard of performance with which assessed performance may be
compared.
Critical/Criticality
Equipment or system where failure may lead to Risk or an Unacceptable
Situation.

Critical Equipment
Equipment or systems where failure may lead to Risk or an Unacceptable
Situation.
.
Critical Machine System
A Machine System, which has been assessed to involve an Unacceptable
Situation if the machine or its protective system should fail. This includes
all failures or malfunctions, which could lead to danger to life, significant
harm to any person or to the environment.
Critical Pipebridges
Structures which support a group of pipelines either on bridges or on a
series of supports whose failure could cause one or all of the pipes to
suffer the loss of containment due to structural failure which could lead to
an Unacceptable Situation.
Critical Piping System
A Piping System which is outside GBHE specifications, or one which is in
such a location that a leak or failure could give rise to an Unacceptable
Situation.
Critical Plant Structures
Structures or buildings the failure of which could lead to a loss of
containment of chemicals, or other potentially hazardous substances,
causing an Unacceptable Situation.
Critical Safety Instrumented System
A Critical Safety Instrumented System is one that protects against hazards
concerned with a risk of death or serious injury to people or of harm to the
environment and (alone, or in conjunction with other measures) makes a
significant contribution towards the reduction of an identified risk. The
system is said to be Critical when the risk is reduced by a factor of 10 or
more to a tolerable level.

Note: On most plants only a small proportion of the trip and alarm
systems are Critical Safety Instrumented Systems. Devices for electric
power protection, safety valves, bursting discs, mechanical interlocks and
fire & security systems are NOT included.
Dike
See Bund.
Dow Index
This is an index of fire, explosion and toxic hazards which may be used for
risk prioritization selection and ranking. (May be used to assist in the
laying out of chemical plant.)
E/I - Electrical/Instrumentation
Synonym for Control / Electrical.
EIA – Environmental Impact Assessment
The process of considering and justifying the impact of a new plant or
significant change on the immediate and general environment.
ELD – Engineering Line Diagram
A drawing showing the process piping, instrumentation and equipment.
Also known as Piping and Instrument Diagram, Process and Instrument
Diagram, PID or P&ID.
EQS – Environmental Quality Standard
A concentration of a substance deemed to be acceptable to the aquatic
environment being considered. The EQS may apply at local, national or
international level.
ES – Environmental Statement
A document considering and justifying the environmental impact of new
plants or significant changes. Submission of an Environmental Statement
to the planning authorities is often a legal requirement.

Electrical Equipment
Within the scope of GEP 2 this definition includes instrumentation.
Electrical System
The interconnection of all the Electrical Equipment to a common source of
electrical energy and includes that source.
FMEA – Failure Mode and Effect Analysis
A systematic, tabular method for evaluating and documenting the causes
and effects of known types of component failures.
FS - Function Specification
Fault Tree
A logic model that graphically portrays the combinations of failures that
can lead to a specific main failure or accident of interest. This generally
follows an ANSI standard N41.4-1976 now superseded by IEC 61025.
See Hazard Analysis.
Formal Design Review
Reviews carried out by the Design Authority on new and Modified Critical
and Controlled Equipment. They should ensure that appropriate design
and construction standards are used to meet the duty and operating
requirements, and that design limits, working limits, protective systems
and inspection requirements are sufficient to control hazards and to
prevent an Unacceptable Situation.
Note: This review is sometimes known as design verification.
GEP – Group Engineering Procedure
Engineering Documents in the GEP series define essential requirements
for compliance with GBHEs Safety, Health and Environmental Standards.
International businesses have their own version of the GEPs.

GG – Group Guideline
Guideline in the Responsible Care Management System (RCMS).
GS – Group Standard
Standard specified in the Responsible Care Management System
(RCMS).
Ground
Any natural material below the land surface.
Groundwater
All subsurface water contained in the Ground and geological formations.
Group Risk
See Societal Risk.
Guide Diagram
A set of guidewords used to stimulate thinking about potential hazards.
There are different guide diagrams for different stages of Hazard Studies
and for different types of processes or operations.
Guidewords
Guidewords used to prompt thoughts.
HAZCON
A what if/checklist based study for construction and demolition activities.
HAZDEM
A what if/checklist based study specifically for demolition activities.

HDS – Hazard Data Sheet
Summary of the SHE hazards of the specified material. Sometimes (US
terminology), referred to as MSDS – Material Safety Data Sheet.
HV – High Voltage
Any equipment or conductor with an operating voltage above 1000 V,
unless otherwise defined in national or local regulations.
Hazard
A Hazard is a physical situation with potential to cause harm to people, the
environment or property. As so defined, Hazards can be associated with
physical, chemical or biological effects in storage, transport or use of
chemicals and in the operation of other assets.
Hazard Analysis or HAZAN
The identification or undesired events that lead to the materialization of a
hazard, the analysis of the mechanisms by which these undesired events
could occur and usually the estimation of the extent, magnitude and
likelihood of any harmful effects. Not to be confused with Process Hazard
Analysis (PHA) which has a specific meaning in the USA. Generally in
GBHE outside North America Hazard Analysis refers to a Fault Tree type
diagram drawn in accordance with GBHE’s conventions.
Hazard Assessment
See Hazard Analysis.
Hazard Control Philosophy
The hazard control philosophy will describe the principles that will be used
for control of significant hazards. Examples are; the use of double blocks
and bleeds for isolation, high pressure design to minimize relief
requirements or to contain explosions, maintenance venting handling,
flaring, computer control systems, etc.

Hazard and Operability (HAZOP) Study
A study carried out by application of guidewords to identify all deviations
from design intent with the potential for undesirable effects on safety,
health, the environment or operability. A general term for studies such as
Hazard Study 3. In the GBHE system it should not be used for any of the
other studies.
Hazard Study
A Hazard Study is one of a set of studies carried out to ensure that
Hazards are identified, understood and properly controlled.
Hazard Studies can be carried out on new or existing processes or on
modifications. Hazard Studies also identify obstacles to operability. The
technique applied depends on the stage of the study; some studies will
use a guide diagram approach to identify hazards and others will be based
more on a checklist approach.
Hazard Study Leader
The person appointed to lead a team through the hazard study process.
The hazard study leader is responsible for the thoroughness of the hazard
study.
Hazardous Event
The occurrence of an incident with a potential for human injury, damage to
property, damage to the environment or some combination of these.
High Hazard Materials
These are:
• Dangerous goods categorized as Packing Group I according to the criteria
of the United Nations’ ‘Orange Book’.
• Compressed gases and liquefied gases.

• ‘Severe Marine Pollutants’ as listed and defined in the International
Maritime Dangerous Goods Code (IMDG Code), and other ecotoxic
substances whose release could result in major contamination.
• Any other substances distributed in such a way that similar risks are
involved.
• As defined in US by 29 CFR 1910.119 Appendix A (actual term used
Highly Hazardous Chemicals).
Hose or Flexible
A complete system including the end connectors, clamps or securing
devices, and the flexible pipe or hose.
IDLH
Maximum concentration (in air) of a substance that has no Immediate
Danger to Life or Health.
Individual Risk
The frequency at which an individual may be expected to sustain a given
level of harm from the realization of specified hazards.
Inspection
See Periodic Inspection.
LE – Lifting Equipment
The term used to describe all forms of Lifting Gear and Lifting Appliance.
LV – Low Voltage
Any equipment or conductor with an operating voltage of 1000 V or below,
unless otherwise defined in national or local regulations.

Lifting Appliance
A machine or component, which using Lifting Gear can raise, lower or
suspend a load. Lifting Appliances include cranes, elevators, or lifts for
personnel and materials, fork-lift trucks, stacker trucks, mobile working
platforms, pulley blocks, runway beams and davits.
Lifting Gear
This includes items such as shackles, slings, hooks, chains and spreader
beams used to connect Lifting Appliances to one another and to connect
Lifting Appliances to loads.
MSDS – Material Safety Data Sheet
US terminology for Hazard Data Sheet.
Machine System
Any reciprocating or rotating device used to produce a change in
properties or conditions within chemical process plants. Examples are
pumps, fans, compressors, turbines, centrifuges and agitators. Included in
the Machine System are any sub-systems required for machine operation,
or safety.
Management System
All of the procedures and instructions, which describe methods of work,
design requirements and operational limits, and which ensure
conformance with legislation, regulations and standards.
Modification/Modify
Examples of Modifications, whether temporary or permanent are listed in
LEP 18/1 Appendix A.
Mond Index
The Mond Index is a rapid hazard assessment technique for use on
chemical plants or in plant design. It enables the potential hazards of plant
units to be identified, assessed and minimized and provides a logical basis
for plant layout. It considers toxic chemicals as well as flammable and
explosive chemicals.

NIHHS - Notification of Installations Handling Hazardous Substances
Regulations 1982 (UK)
OHS - Occupational Health Statement
OSHA - Occupational Safety and Health Administration of the US
Department of Labor
Operational Hazard Assessment
Studies of materials or mixtures to assess their potential for runaway
reactions, spontaneous combustion, explosion ignition conditions and
effects.
Other Critical Pressure Equipment
Equipment such as Atmospheric Pressure Storage Tanks, silos, hoppers
and furnaces that have been selected for registration. It does not include
Pressure Vessels, Piping Systems, Pressure Relief Streams, Protective
Devices and Flexibles and Hoses.
Note: Registration is considered when the equipment is situated where a
leak or failure could cause an Unacceptable Situation, or if use of the
equipment could involve Risk.
PCB - Poly Chlorinated Bi Phenyls
Highly toxic and environmentally damaging materials.
PES – Programmable Electronic System
A computer based system that controls, protects or monitors the operation
of plant, utilities or services. These include programmable logic controllers
(PLC), supervisory computers, microprocessor applications and
distributed control systems. They may also be found in packaged
equipment, measuring elements on load cells and analyzers.
PFD - Probability of Failure on Demand
The fraction of the time a protective device is not available due to some
type of failure. Formally called FDT or Fractional Dead Time.

PFD - Process Flow Diagram
A representation of the process flowsheet including main plant items and
their connections.
PHA – Process Hazard Analysis
As defined by OSHA “A thorough, orderly, systematic approach for
identifying, evaluating, and controlling the hazards of processes involving
highly hazardous chemicals.” Approved methodologies are ‘What If’,
‘Check List’, ‘What If/Check List’, Hazard and Operability Study
(HAZOP), Failure Mode and Effect Analysis (FMEA), Fault Tree Analysis
or an appropriate equivalent methodology. GBHE’s Hazard Study
Methodology meets PHA requirements.
PHR – Periodic Hazard Review
PHR – Process Hazard Analysis Revalidation (in USA legislation)
Periodic review and audit of the safety management of a process
subsequent to commissioning. In GBHE, PHR based on Hazard Study 2 is
a technique developed to meet SHE Assurance requirements.
P&ID – Piping and Instrument Diagram
See ELD (Engineering Line Diagram).
PLC - Programmable Logic Controller
PSM - Process Safety Management
In the US this usually refers to the OSHA PSM rule, 29 CFR 1910.119,
The Process Safety Management of Highly Hazardous Chemicals. The
objective of this legislation is to protect workers from toxic emissions, fires
and explosions from operations involving hazardous chemicals. Parallel
legislation to the EPA’s RMP rule, which is focused on the protection of
the public.

Periodic Inspection
A careful and critical scrutiny of the registered equipment, systems or
installation to assess its actual condition and whether it is safe to use for
the period up to the next Periodic inspection. The term testing is often
used for safety instrumented systems.
Piping System
A section of pipework including piping and pipework components such as
flanges and fittings, valves, bellows, anchors, supports, linings, insulation
and protection.
Pressure Relief Stream
Comprises the pipework, any Protective Device and associated alarms
and interlocks, and other equipment between the equipment to be
protected and either the exit to atmosphere or a downstream vessel. A
Pressure Relief Stream may include a discharge header being fed by
other Pressure Relief Streams.
Pressure System
Pressure vessels, Atmospheric Pressure Storage Tanks, piping systems,
Pressure Relief Streams and other pressure containing equipment.
Pressure Vessel
A container or structural envelope of any capacity subject to either internal
or external pressure. The term includes process vessels, reactors, heat
exchangers and vessels for the storage of fluid under pressure. In North
America the term is used for vessels designed for and subject to a
pressure of 15 psi g or greater.
Project Manager
The Project Manager is the manager of a Capital Project (including
site/facility controlled projects), appointed by the Responsible Executive to
be responsible for the implementation of the project from inception to
completion of Commissioning (or other milestone agreed with the
business).

Project SHE Dossier
See SSHE dossier.
Project Specification
The project specification is developed from the process specification and
provides the formal basis for the cost estimate leading to sanction and
detailed design.
Protective Device
Any automatic device, which protects equipment from excessive internal
or external pressure, such as a safety valve, a pressure vacuum relief
valve, a vacuum relief valve, a bursting disc, an atmospheric vent, an
overflow, a lute, a flame trap or an explosion door, together with any
accessories such as interlocks and alarms.
QRA - Quantified Risk Assessment
RCRA - Research Conservation and Recovery Act
US legislation owned by the Federal EPA. Detailed requirements may vary
from state to state. Deals with the disposal of hazardous liquid and solid
wastes.
RMP – Risk Management Program
40 CFR Part 68 Chemical Accident Prevention Provisions, US Federal
EPA (Environmental Protection Agency) Rule to protect the public from
toxic emissions, fires and explosions arising from operations involving
hazardous chemicals. Parallel legislation to OSHA’s PSM regulation
29 CFR 1910.119 which is focused on the protection of workers.
Recognized Good Practice
The knowledge contained in national and international standards and
codes of practice, Group or industry guidance, professional knowledge,
learning from events, and similar sources, which require professional
judgment in their application. Allowance should be made for international
differences in the practice used to achieve conformance with a given SHE
standard.

Register
A list of equipment subject to Registration. Each item is to be given a
unique number so that it can be easily found and a record kept.
Registration/Registered
Registration within GBHE is the formal status given to selected
plant/equipment/systems so as to ensure integrity.
Requirements for Registration include:
(a) Allocating and making such equipment/systems with a unique
identification number;
(b) Creating and maintaining a record file containing key information
relating to design, commissioning, construction, testing, Periodic
Inspections, Repairs and Modifications;
(c) Inclusion in a notification system which displays the next due
Periodic Inspection date and any overdue inspections.
Repair
A Repair involves restoration of equipment in accordance with the original
design, parts and material specifications. Other work should be regarded
as a Modification.
Responsible Care Management System (RCMS)
GBHE Safety, Security, Health and Environmental Policy Standards and
Guidelines.
Responsible Engineers (Mechanical, Electrical, Civil or Instrument)
The responsibilities of the Responsible Engineer are specified in the
Group Engineering Procedures. It is essential that the individual have both
the competence and the authority to fulfill the accountabilities. On
appointment the Responsible Engineer shall carefully consider such
factors and refer any concerns to the Responsible Executive and, if
necessary, the GBHE Engineering Manager.

The Responsible Engineer is responsible for ensuring the appointment of
the appropriate key individuals for the production unit/facility.
Responsible Executive
The person identified by the Business, Region or Group Department as
having the following responsibilities that are included in each GEP:
(a) Ensuring that local engineering procedures are provided in
accordance with the Group Engineering Procedure, and that they
are implemented;
(b) Approval, in consultation with the GBHE Engineering Manager (or
nominee), of the appointment of Responsible Engineers and other
key individuals required by the Group Engineering Procedure;
(c) Ensuring that staff with the required competence are appointed in
writing;
(d) Ensuring that systems for GEP compliance audits are established.
Guidance on the appointment of Responsible Engineers can be found in
GBHE-EN-003.
Risk
Risk is the likelihood of a specified level of harm to people, the
environment or property or that adverse effects will be expressed as a
result of exposure to hazard.
It may be either a frequency (the number of specified events occurring in
unit time) or a probability (the probability of a specified event following a
prior event), depending on the circumstances.
Risk Assessment
The evaluation of the likelihood of undesired events and the likelihood of
harm or damage being caused, together with the value judgments made
concerning the significance of the results.

SARA – Superfund Amendments and Reauthorization Act
US environmental regulation that includes chemical inventory reporting
and local emergency planning.
SEVESO
Refers to European Union SHE legislation 82/501/EEC enacted in
response to the chemical disaster at Seveso, Italy. In UK embodied in
CIMAH and, more recently, COMAH.
SHE Impact Study
A study carried out, according to GG 17.2 (now a reference document), at
an early stage in process development which focuses on assessing the
SHE impact of a process and employing the use of Inherent SHE
principles.
SHED – Safety, Health and Environmental Dossier
SIS – Safety Instrumented System
A system composed of sensors, logic solvers, and final control elements
for the purpose of taking the process to a safe state when pre-determined
conditions are violated to protect safety, health or the environment. They
consist of the following:
A trip system: an automatic instrument system used to prevent
hazardous events from arising. It measures one or more relevant process
parameters and if the value of one (or a pre-defined combination) of these
reaches preset limits (which anticipate the hazardous condition by a safety
margin) then it takes action to make the plant safe.
An alarm system: a warning device that provides a plant operator with
information that a predefined hazardous condition is imminent. The
information is displayed by a steady or flashing light or a message on a
computer screen, and is usually accompanied by an audible tone to attract
the operator’s attention.

An interlock: an instrument system which prevents potentially hazardous
or otherwise undesirable actions from being taken unless other actions
have been taken to make it safe (e.g. a door into a machine might be
interlocked so that it cannot be opened unless the machine is stopped and
electrically isolated). Interlocks differ from trips in that they do not require
to be reset manually.
A standby control system: a system that remains inactive during normal
process conditions. Its set point is adjusted to the limit of acceptable
process operation, so that when the controlled parameter reaches this
limit the standby control system comes into operation to ensure the limit is
applied.
SSHE dossier
Essential information relating to the design, operation and maintenance of
a plant.
Significant Environmental Harm
This is evident damage to plant or animal life or contamination of Ground,
Groundwater or surface water to an extent that would impair the fitness of
these media for beneficial use.
Site Responsible Engineer
The person to whom defined responsibilities are given by the Responsible
Executive to ensure that management systems are in place to implement
the requirements of the relevant GEP, and to ensure that the appropriate
management decisions are made. The appointed Site Responsible
Engineer needs to recognize limitations in expertise and seek technical
advice from others deemed to be competent in the GEP topic. In
delegating such technical judgments, the Site Responsible Engineer does
not delegate accountability. It is essential that the individual has both the
competence and the authority to fulfill the required accountabilities, and
guidance is given in GEN-003.
Societal Risk
The relationship between frequency and the number of people suffering
from a specified level of harm in a given population from the realization of
specified hazards. Now becoming known as Group Risk.

TSCA – Toxic Substances Control Act
This is US legislation owned by the EPA that regulates chemicals in the
workplace.
Type A Trip
A trip that is a safety instrumented system (SIS) qv.
Type B Trip
A trip whose failure results in a significant business loss but not in an
unacceptable situation with respect to safety or the environment.
URS – User Requirement Specification
General specification specifying performance requirements usually applied
to control/electrical systems.
Unacceptable Situation
Where there is a significant probability of serious harm to people or to the
environment. Within the above general definition the Site Responsible
Engineer or other appropriate persons are required to make the judgment
based on the particular circumstances. At Business discretion, serious
loss of production may be regarded as an Unacceptable Situation.
VCS – Vent Collection System
Vessel
A Vessel may be either a Pressure Vessel or an Atmospheric Pressure
Storage Tank.

Hazard Study Process Glossary

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