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SEMI S2-0703a E © SEMI 1991, 2004 28 section can b e shown by demonstrating ambi ent air concentrations to be less than 25% of the OEL, in the anticipated worst-case personnel breathing zone , during maintenance activiti…

SEMI S2-0703a

NOTE 106: Sail switches (switches that are connected to a

lever that relies upon air velocity to activate) are generally not

recommended.

NOTE 107: It is recommended that the pressure or flow

measuring point be located upstream of the first damper.

NOTE 108: Section 11 contains provisions for safety

interlocks.

22.4.1 When the exhaust falls below the prescribed set

point, an alarm should be provided within audible or

visible range of the operator, and the process equipment

should be placed in a safe stand-by mode. A time delay

and exhaust setpoint for the equipment to go into

standby mode may be allowable, based on an

appropriate risk assessment. The system should be

capable of interfacing with the facility alarm system.

NOTE 109: It is recommended that non-HPM chemical

process exhaust be equipped with audible and visible

indicators only.

22.4.2 Exhaust flow interlocks and alarms should

require manual resetting.

22.4.3 Exhaust flow interlocks should be fault-tolerant.

22.5 Equipment and equipment components should be

designed using good ventilation principles and practices

to ensure chemical capture and to optimize exhaust

efficiency (see Appendix 2).

NOTE 110: It is recommended that exhaust optimization be

achieved with total equipment static pressure requirements of

–1 to –38 mm (–0.05 to –1.5") H

O (see also Section A2-1 of

Appendix 2, and Section 8.3.6.1 of SEMI S6-93).

23 Chemicals

23.1 The manufacturer should generate a chemical

inventory identifying the chemicals anticipated to be

used or generated in the equipment. At a minimum, this

should include chemicals in the recipe used for

equipment qualification or “baseline” recipe, as well as

intended reaction products and anticipated by-products.

Chemicals on this list that can be classified as

hazardous production materials (HPMs), or odorous

(odor threshold < 1 ppm) or irritant chemicals

(according to their material safety data sheets), should

also be identified.

23.2 A hazard analysis (see Section 6.8) should be

used as an initial determination of chemical risk as well

as to validate that the risk has been controlled to an

appropriate level.

23.2.1 The hazard analysis, at a minimum, should

address the following conditions:

 potential mixing of incompatible chemicals;

 potential chemical emissions during routine

operation;

 potential chemical emissions during maintenance

activities; and

 potential key failure points and trouble spots (e.g.,

fittings, pumps).

23.2.2 All routes of exposure (e.g., respiratory, dermal)

should be considered in exposure assessment.

23.3 The order of preference for controls in reducing

chemical-related risks is as follows:

23.3.1 substitution or elimination (see also Section

21.2.2);

23.3.2 engineering controls (e.g., enclosure,

ventilation, interlocks);

23.3.3 administrative controls (e.g., written warnings,

standard operating procedures);

23.3.4 personal protective equipment.

23.4 The design of engineering controls (e.g.,

enclosure, ventilation, interlocks) should include

consideration of (see also Appendix 3):

 pressure requirements;

 materials incompatibility;

 equipment maintainability;

 chemical containment; and

 provisions for exhaust ventilation (see Section 22).

23.5 During equipment development, the supplier

should conduct an assessment that documents

conformance to the following airborne chemical control

criteria (see also Appendix 2). All measurements should

be taken using recognized methods with documented

sensitivities and accuracy. A report documenting the

survey methods, equipment operating parameters,

instrumentation used, calibration data, results, and

discussion should be available.

23.5.1 There should be no chemical emissions to the

workplace environment during normal equipment

operation. Conformance to this section can be shown by

demonstrating ambient air concentrations to be less

than 1% of the Occupational Exposure Limit (OEL) in

the worst-case personnel breathing zone. Where a

recognized method does not provide sufficient

sensitivity to measure 1% OEL, then the lower

detection limit of the method may be used to satisfy this

criterion.

23.5.2 Chemical emissions during maintenance

activities should be minimized. Conformance to this

SEMI S2-0703a

section can be shown by demonstrating ambient air

concentrations to be less than 25% of the OEL, in the

anticipated worst-case personnel breathing zone, during

maintenance activities.

23.5.3 Chemical emissions during equipment failures

should be minimized. Conformance to this section can

be shown by demonstrating ambient air concentrations

to be less than 25% of the OEL, in the anticipated

worst-case personnel breathing zone, during a realistic

worst-case system failure.

NOTE 111: The use of direct reading instrumentation under

simulated operating, maintenance, or failure conditions is the

preferred measurement method. Where used, it is

recommended that the sample location(s) be representative of

the worst-case, realistic exposure locations(s). It is

recommended that the peak concentration be directly

compared to the OEL to demonstrate conformance to Sections

23.5.1–23.5.3.

NOTE 112: It is recommended that integrated sampling

methods be used when direct-reading instrumentation does

not have adequate sensitivity, or when direct-reading

technology is not available for the chemicals of interest.

Where integrated sampling is used, it is recommended that the

sample duration and locations(s) be representative of the

worst-case, realistic, anticipated exposure time and locations.

The resulting average concentration is directly compared to

the OEL to demonstrate conformance to Sections 23.5.1–

23.5.3.

NOTE 113: Tracer gas testing (see SEMI F15 for an

acceptable method) may be used when direct-reading

instrumentation does not have adequate sensitivity, or when

direct-reading technology is not available for the chemicals of

interest. Tracer gas testing should be used where testing

conditions may be hazardous (e.g., system failure simulation

with potential release of hazardous gas to atmosphere). It is

recommended that tracer gas testing be used only when an

accurate rate of chemical emission can be determined. Where

used, it is recommended that the sample location(s) be

representative of the worst-case, realistic exposure location(s).

23.5.4 Chemical emissions outside the enclosure

during a realistic worst-case system failure should be

less than the lower of the following two values: 25% of

the lower explosive limit (LEL), or 25% of the OEL.

23.6 Equipment that uses hazardous gases may require

continuous detection and, if so, should have sample

points mounted in the equipment, or have

recommended sampling points identified in the

equipment installation instructions. Where the gas

supply is part of or controlled by the equipment, the

equipment should be able to accept a signal from an

external monitoring device and shut down the supply of

the gas.

23.7 Appropriate hazard warning labels should be

placed at all chemical enclosure access openings.

24 Ionizing Radiation

24.1 This section covers equipment that produces

ionizing radiation (e.g., X-rays, gamma rays) or uses

radioactive sources.

24.2 Accessible emissions of ionizing radiation should

be designed as low as reasonably achievable. This

criteria can be met by demonstrating conformance to

the provisions in Sections 24.2.1 and 24.2.2 and

Appendix 4.

24.2.1 Accessible levels of ionizing radiation during

normal operations should be less than 2 microsieverts

(0.2 millirem) per hour above background. See also

Table A4-1 of Appendix 4.

24.2.2 Accessible levels of ionizing radiation during

maintenance and service procedures should be less than

10 microsieverts (1 millirem) per hour above

background. See also Table A4-1 of Appendix 4.

24.2.3 Access to radioactive contamination or internal

exposure (e.g., inhalation, ingestion) to radioactive

materials should be minimized. The hazards and

controls for the prevention of personnel contamination

and internal exposures should be detailed in the

operation and maintenance manuals.

NOTE 114: The use of radioactive material is strictly

regulated around the world. Import, export, and transportation

of radioactive materials is also highly regulated. Licenses may

be required to possess, use, and distribute radioactive

materials.

NOTE 115: Many regions require both user and import

licenses, and the timely acquisition of these licenses depends

on the information provided by the equipment supplier.

NOTE 116: Radiation producing machines are also regulated

around the world. Regulations and licensing requirements

may cover activities such as importing, exporting, installing,

servicing and using radiation producing equipment.

24.2.4 The manufacturer should supply, in the user

documentation, a contact phone number and address for

the manufacturer’s radiation safety support personnel.

24.3 Equipment should be designed to minimize access

or exposure to ionizing radiation during normal

operation, maintenance, and service. Potential

exposures should be controlled in the following order of

preference:

24.3.1 Engineering Controls — Engineering controls

(e.g. shielding, interlocks) should be the primary

mechanism to minimize emission of ionizing radiation

or access to ionizing radiation.

24.3.1.1 Radiation shielding for the equipment

facilities connections (e.g., gas and exhaust lines)

should be designed such that removal and replacement

of the shielding during installation is minimized.

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24.3.2 Non-defeatable safety interlocks should be

provided on barriers preventing maintenance access to

radiation fields in excess of 10 microsieverts (Sv) or 1

millirem per hour.

24.3.3 Administrative Controls — When

administrative controls (e.g., distance, time, standard

operating procedures, labeling) are to be used, the

equipment supplier should provide detailed

documentation explaining the use of the administrative

controls.

24.4 Equipment utilizing or producing ionizing

radiation should be labeled appropriately.

NOTE 117: Label contents are typically controlled by

regulation in the country in which the equipment is to be used.

24.5 The manufacturer should conduct an assessment

to document conformance to the criteria specified in

Sections 24.2.1 through 24.2.2 during normal

equipment operation, maintenance, and service.

24.5.1 A radiation survey should be used to confirm

design compliance and serve as a baseline survey (see

also Table A4-1 of Appendix 4).

24.5.2 Measurements should be taken using recognized

methods with documented sensitivities and accuracy. A

report documenting the survey methods, equipment

operating parameters, instrumentation used, calibration

data, source locations, results, and discussion should be

made available.

24.5.3 If supplemental administrative controls are

recommended based on survey results or calculations, a

discussion should be provided in the operations and

maintenance manuals describing the source locations,

radiation levels, and recommended control measures.

NOTE 118: Ionizing radiation sources must be registered or

licensed according to the regulations of the country of

destination. These radiation sources must conform to the

regulations of central or local government agencies,

whichever is stricter.

NOTE 119: It is recommended that equipment containing

radioactive materials should demonstrate conformance to

licensing with local regulatory agencies prior to shipment.

NOTE 120: Equipment that uses particle acceleration in its

process has the potential for generating ionizing radiation as a

result of nuclear interactions between the accelerated particles

and various materials. These materials can include materials

of construction of the equipment, accumulated residual

process materials in the equipment, and the target materials.

25 Non-Ionizing Radiation and Fields

25.1 This section covers equipment that produces non-

ionizing radiation, except laser sources, in the following

categories:

 static electric and magnetic (0 Hz),

 sub-radio frequency electric and magnetic fields

( < 3 kHz),

 radio frequency (3 kHz–300 GHz),

 infrared radiation (700 nm–1 mm),

 visible Light (400 nm–700 nm), and

 ultraviolet Light (180–400 nm).

25.2 Potentially hazardous non-ionizing radiation

emissions that are accessible to any personnel should be

limited to the lowest practical level. This criterion can

be met by demonstrating conformance to the following

provisions:

EXCEPTION: Emissions of non-ionizing radiation

exceeding the cardiac pacemaker limits in Appendix 5

but less than the levels in Sections 25.2.1 and 25.2.2

should be identified with appropriate labeling. See also

Section 25.5.1.

25.2.1 Accessible levels of non-ionizing radiation

during normal operations are less than the Operator-

Accessible Limit (see Appendix 5);

25.2.2 Accessible levels of non-ionizing radiation

during maintenance and service procedures are less

than the Maintenance- and Service-Accessible Limit

(see Appendix 5).

25.3 Sources of potentially hazardous non-ionizing

radiation should be identified in the operation and

maintenance manuals, and appropriate parameters

listed. Parameters include frequency, wavelength,

power levels, continuous wave or pulsed (see also

Appendix 5). If pulsed, parameters also include the

pulse repetition rate, pulse duration, and description of

the pulse waveform.

EXCEPTION: Visible sources which are intended to be

viewed or which provide illumination (e.g., display

panels, visible alarm indicators), and are not lasers, do

not need to be identified.

NOTE 121: It is recommended that UV/IR generators that

are part of fire protection test apparatus, and are provided

with the equipment, be considered as possible sources of

potentially hazardous non-ionizing radiation.

25.4 Equipment should be designed to minimize access

or exposure to non-ionizing radiation during normal

operation, maintenance, and service. Potential

exposures should be controlled in the following order of

preference:

25.4.1 engineering controls (e.g., enclosure, shielding,

guarding, grounding, interlocks);