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SEMI S21-1103 © SEMI 2003 6 8 Control of Hazardous Energy NOTE 15: Control of hazardous energy is commonly known as lock and tag or Lockout/Tago ut. US OSHA regulation: 29 CFR 1910.147 is one location wher e detailed inf…
SEMI S21-1103 © SEMI 2003 5
7.2.7.2 Employers should train their workers on proper
implementation of the program.
7.3 Chemical Handling and Storage
NOTE 9: Information on chemicals used in the area and the
facility-operator-required personal protective equipment
(PPE) is the responsibility of the facility operator and should
be available in the work area according to regulations for the
location.
NOTE 10: Persons providing transient workers into the
facility should coordinate to determine if there are any
differences between the facility requirements for PPE and the
worker employer requirements for PPE.
7.3.1 All workers should be trained on the chemical
hazards, the proper use of the PPE, and the limitations
of the PPE.
7.3.2 Chemical information should be presented to
workers during training in a clearly understandable
format (such as a table) and should include chemical
names, chemical formulas, hazardous properties
(flammable, corrosive), chemical states (solid, liquid, or
gas), and other hazard information.
NOTE 11: It is recommended that users of this document
refer to Section 12 Personal Protective Equipment for
additional information on protection from chemical exposure.
7.3.3 Further information on typical chemical
categories and their related hazards is provided in Table
A1-1 of Appendix 1.
7.3.4 When operation, maintenance, or service tasks
may include exposure to chemical mists, fumes, or
vapors, the tasks should be conducted with adequate
ventilation.
7.3.4.1 If there is a possibility of insufficient
ventilation, employers are responsible for ensuring that
their workers wear respiratory protective equipment.
7.3.5 If maintenance or service tasks require access to
chemically contaminated areas of the equipment, PPE
may be needed, and implementation of decontamination
procedures may be necessary.
7.3.6 Workers should be trained to know when it is
appropriate to clean up chemical spills. The amount that
may be cleaned up is completely dependent upon the
user’s site hazardous material policies.
7.3.7 Workers should not attempt to clean up large or
unknown spills without proper training. In these
circumstances, the ERT should be contacted.
7.4 Incompatible chemicals should not be mixed or
stored together in the same spill control area unless
adequate controls are provided to avoid mixing of
chemicals or creation of a risk of fire and explosion.
NOTE 12: Specific chemical separation requirements are
defined by local regulation.
7.4.1 Chemical containers should be stored in a
designated location based on hazard categories.
Containers should be segregated based on
incompatibility risks.
7.4.2 Compressed gas cylinders should be secured
upright at all times. When cylinders are not in use,
outlet and valve protective caps should be in place.
NOTE 13: Depending on the gas hazard, some jurisdictions
require non-combustible securing devices (e.g., chains).
NOTE 14: Cylinders within the semiconductor
manufacturing equipment may be installed horizontally if the
equipment manufacturer determines this is compatible with
the cylinder type to be used.
7.5 Protection Against Unexpected Release
7.5.1 Hazardous Energy Control or Lockout/Tagout
procedures should be used to protect workers from the
unexpected release of hazardous energies associated
with pressurized gas, pressurized liquid chemicals or
other (e.g., chemical reaction) energy. The Control of
Hazardous Energy section of this document applies to
all gaseous and liquid chemical energy during
maintenance and service tasks.
7.6 Oxygen Deficiency
7.6.1 If work is to be performed where oxygen
deficiency is possible, (e.g., inside a confined space,
near a high volume inert gas flow), the oxygen content
of the atmosphere should be monitored.
7.6.2 If a hazard exists, appropriate worker protection
measures should be implemented prior to entry.
If the
oxygen content decreases to below 19.5%, workers who
are not provided with supplied air respirators have to
leave.
7.6.3 If elimination of oxygen deficiency is not
practical, workers should use appropriate PPE as a
means of working safely in an oxygen deficient
environment.
7.6.4 The worker should be educated on the hazards
and the necessary protective measures associated with
oxygen deficient environments.
7.7 Chemical Waste
7.7.1 Spent chemical drains should be separated to the
extent that chemical reactions will not cause damage to
drain materials of construction or other chemical
reaction hazards. The user’s instructions should be
followed to avoid potential hazards.
7.7.2 Solid waste should be placed in the appropriate,
labeled waste container based upon user’s instructions.
SEMI S21-1103 © SEMI 2003 6
8 Control of Hazardous Energy
NOTE 15: Control of hazardous energy is commonly known
as lock and tag or Lockout/Tagout. US OSHA regulation: 29
CFR 1910.147 is one location where detailed information can
be found.
8.1 Hazardous Energy Control (lockout/tagout) is a
method for isolating sources of hazardous energy from
equipment and protecting workers from accidental
release of the energy.
8.2 Suppliers should identify all tasks that could be
affected by hazardous energy, (e.g., electrical,
chemical, mechanical, hydraulic, pneumatic, stored,
gravity or thermal) and should provide procedures for
effectively isolating such energy and safely restoring
the energy after performing each work task.
8.3 Safe De-Energized Work Procedures
8.3.1 Preparation
NOTE 16: This list is not intended to be in any specific order
and the order may be changed to reflect individual conditions.
a. Identify the task to be performed.
b. Identify all energy sources and the location of the
means of isolation for each source.
c. Notify potentially affected persons that the work
will be performed.
d. Locate hazardous energy control procedures for the
specific system and task.
e. Shut down equipment using normal shut down
procedures.
f. Isolate all appropriate energy sources in the order
and manner specified in the procedures.
NOTE 17: Certain procedures may require modification to
account for factory-located energy isolation devices and to
meet local regulatory requirements.
g. For electrical energy, turn off the power at the
appropriate disconnection point.
NOTE 18: If regulations have allowed multiple electrical
energy sources, (e.g., main power, emergency power, UPS
power) all sources of power must be identified. Each source
that may expose the worker should be isolated to ensure safe
working conditions.
h. Verify absence of hazardous voltage at the
equipment side of the disconnecting mechanism with an
appropriate test device.
• The test device should be checked for correct
operation before and after testing for the presence
of hazardous electrical energy.
i. Ensure that all energy is at zero state and that any
capacitors or other electrical energy storage devices are
fully discharged or isolated.
j. Follow any special steps needed to eliminate stored
energy (e.g., liquid or gas pressure, capacitors,
compressed springs, support of a raised mass).
k. Each person performing work should apply a
locking device (under exclusive control of the worker)
and a tag to each isolated energy source.
NOTE 19: Some jurisdictions allow for group lockout
capability. Entities creating procedures and persons
performing lockout should understand the procedures for the
location.
l. Verify that energy is no longer present (e.g., check
pressure, presence of liquid, weight, temperature)
8.3.2 Performing Work Tasks
8.3.2.1 Work may only be performed by persons who
are trained to work on the specific equipment.
8.3.2.2 De-energized work may only occur after the
person has isolated the energy and applied a lock and
tag to the energy isolation device.
8.3.2.3 Work continuing past shift change should be
provided with special lockout transfer procedures (that
are usually controlled by the user) to ensure locks are
applied by the workers on the new shift and that
workers on then previous shift have removed their
locks.
8.3.3 Restoration of Energy
8.3.3.1 Remove all hand tools, parts and other
miscellaneous items may have been inadvertently left in
the area during the work.
8.3.3.2 Ensure all safety devices have been restored.
8.3.3.3 Notify all personnel who could be affected by
the potential hazard.
8.3.3.4 Remove energy isolation devices (e.g., locks,
tags blinds, barriers) in the order specified in the task
procedures.
8.3.3.5 After verifying that all persons are clear, restart
the system.
8.3.3.5.1 Apply energy in the proper sequence for safe
restart (e.g., power to interlocks and controls before
main energy, power to interlocks before chemical re-
pressurization).
8.3.3.6 Verify equipment is operating properly.
8.3.3.7 Reset all outer enclosure interlocks and secure
outer enclosures.
SEMI S21-1103 © SEMI 2003 7
9 EEW at Hazardous Voltage or Energy Levels
9.1 Hazardous electrical energy should be isolated
whenever it is possible to perform the work with the
equipment non-energized.
9.2 When electrical energy cannot be isolated due to
the type of work to be performed (e.g., trouble-
shooting, power supply adjustment), suppliers should
identify all tasks that include electrical-energized work
and should provide procedures for safely accomplishing
such work.
9.2.1 Facility operators should verify, modify if
necessary, and approve procedures before EEW is
performed at the facility.
NOTE 20: Appropriate levels of PPE for EEW can only be
calculated with knowledge of the energy available from the
source (e.g., sub-station, transformer) that provides power
from the facility to the equipment circuit.
9.3 EEW or Working on Energized Electrical Circuitry
9.3.1 Supplier should notify the user of any EEW that
may be required.
NOTE 21: Routine testing of circuits may be included in the
definition of EEW in some circumstances and in some
jurisdictions.
9.3.1.1 Two or more qualified persons should perform
EEW, except for the routine testing of circuits.
9.3.1.2 One worker should always have access to and
be ready to de-energize the system by operating the
appropriate disconnecting device.
NOTE 22: Some jurisdictions or users may require persons to
be trained in emergency rescue procedures such as cardio
pulmonary resuscitation (CPR) electrical shock first-aid, and
extracting a person from an energized circuit.
9.3.1.3 EEW should only be performed by workers
wearing appropriate electrical PPE and natural fiber
clothing for protection against shock, arc, flash, or burn.
NOTE 23: Electrical PPE manufacturers have been testing
certain models of natural fiber or electrical protective
synthetic fiber (e.g., Monofilament Nomex) for clean room
purposes, however, supplier personnel and users should
coordinate the use of clothing that is acceptable in the specific
factory.
9.3.1.3.1 Clothing made from synthetic materials such
as acetate, nylon, polyester, or rayon, either alone or in
blends with cotton, should not be worn for EEW at
hazardous energy levels where the exposure for arc,
flash or burn exists; because it can melt and therefore
fail to provide adequate protection.
NOTE 24: Normal clean room clothing is made from
synthetic fabrics and caution should be taken to provide
adequate protection.
NOTE 25: A Hazard/risk analysis may be used to determine
available fault current and incident energy level in J/cm
2
.
These calculated levels establish the level of natural fiber,
calorie-rated flame resistant clothing and electrical PPE
necessary for protection. Calculation formulas and
hazard/risk analysis methods are available in documents such
as ANSI/NFPA 70E.
9.3.1.4 Metal jewelry (e.g., such as watches, rings,
metal framed eyeglasses, and body-piercing jewelry)
should be removed during EEW.
9.3.1.5 During EEW, access to the immediate work
area should be restricted from unqualified workers by
the use of barricades, safety signs, safety cones, safety
tape or a human guardian.
9.4 Safe EEW procedures should be provided by
supplier and should include the following:
a. Verification of valid reasons for performing the
work energized.
b. Identify electrical energy sources and the location
of the means of isolation for each source.
NOTE 26: Identification is required to ensure that workers
know how to remove energy if an emergency develops during
the work task.
c. When the hazard is remote from the equipment
controls, the warning should also be provided at the
point of the hazard.
d. When the EEW is complete, workers should
restore the equipment to its original state and ensure
that all safeguards are restored and interlocks are
functioning properly.
10 Radiation-Producing Equipment
10.1.1 Ionizing Radiation
10.1.1.1 Initial radiation surveys should be performed
as required by regulations to verify that radiation
shielding is installed.
10.1.1.1.1 Additional radiation surveys should be
conducted following maintenance or service tasks to
ensure shielding remains in place, and is effective.
10.1.1.2 Access of unauthorized persons, to working
areas where there is a risk of exposure to hazardous
levels of radiation, should be restricted.
10.1.1.3 If work associated with radiation is required,
the workers should be trained on the hazard
characteristics and appropriate protection measures,
including safe handling, use, and shielding.
NOTE 27: Certification of the people performing the work
may be required, depending on the work to be performed or
the type of radiation.