ASTM E1548-93(1998)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 1548 – 93 (Reapproved 1998)
Standard Practice for
Preparation of Aerospace Contamination Control Plans
This standard is issued under the fixed designation E 1548; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope E 1235M Test Method for Gravimetric Determination of
Nonvolatile Residue (NVR) in Environmentally Con-
1.1 This practice is intended to assist in the preparation of
trolled Areas for Spacecraft
formal plans for contamination control, especially of aerospace
E 1549M Specification for ESD Controlled Garments Re-
critical surfaces. Requirements may be established at the
quired in Cleanrooms and Controlled Environments for
systems level, either by the customer or the systems integrator,
Spacecraft for Non-Hazardous and Hazardous Operations
or at the subsystem level. Subsystem requirements may be
F 50 Practice for Continuous Sizing and Counting of Air-
imposed by the responsible subsystem supplier or they may be
borne Particles in Dust-Controlled Areas and Clean Rooms
flowed down from the systems organization (4.7). The extent
Using Instruments Capable of Detecting Single Sub-
of detail and level of cleanliness required can vary with the
Micrometre and Larger Particles
particular application and type of hardware being built, but all
F 303 Practices for Sampling Aerospace Fluids from Com-
aspects of contamination control must be included in a final
ponents
plan. Therefore, each of the following elements must be
F 312 Methods for Microscopical Sizing and Counting
considered for inclusion in a contamination control plan
Particles from Aerospace Fluids on Membrane Filters
(CCP):
2.2 Government Standards:
1.1.1 Cleanliness requirements for deliverable hardware
FED-STD-209 Airborne Particulate Cleanliness Classes in
addressing particulate, molecular, or biological contaminants
Cleanrooms and Clean Zones
or combination thereof. Specify contamination limits and any
MIL-STD-1246 Product Cleanliness Levels and Contami-
budget allocations.
nation Control Program
1.1.2 Implementation plans to achieve, verify, and maintain
USAF Tech Order 00-25-203 Contamination Control of
the specified cleanliness requirements. Specify material and
Aerospace Facilities, U.S. Air Force
process controls, cleaning techniques, verification tests, pro-
tection and prevention plans, transportation controls, and
NOTE 1—The Institute of Environmental Sciences has several Recom-
corrective action for discrepancies. mended Practices which may also be useful in the preparation of a CCP.
1.1.3 Environmental controls including clean facilities to
3. Terminology
be used, facility maintenance, and monitoring schedule.
1.1.4 Personnel and operational controls including operat- 3.1 Definitions:
ing procedures, restrictions, training, motivation, and organi- 3.1.1 bidirectional reflectance distribution function
(BRDF)—the scattering properties of light reflected off sur-
zational responsibilities including the organization or indi-
vidual for implementation and verification of the CCP. faces, expressed as the ratio of differential outputs of radiance
divided by differential inputs of radiance. Surface contami-
2. Referenced Documents
nants scatter the incident radiation in all directions and with
2.1 ASTM Standards: variable intensities; BRDF is a method to quantify the spatial
E 595 Test Method for Total Mass Loss and Collected distribution of the scattered energy.
Volatile Condensable Materials from Outgassing in a 3.1.2 biological contamination—living material such as
Vacuum Environment algae, bacteria, fungus, etc. which is capable of reproducing,
E 1216 Practice for Sampling for Surface Particulate Con- thus being an increasing contaminant source.
tamination by Tape Lift
This practice is under the jurisdiction of ASTM Committee E-21 on Space
Simulation and Applications of Space Technology and is the direct responsibility of
Subcommittee E21.05 on Contamination. Annual Book of ASTM Standards, Vol 14.02.
Current edition approved June 15, 1993. Published August 1993. Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
Annual Book of ASTM Standards, Vol 15.03. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 1548 – 93 (1998)
3.1.3 budget allocation—the itemized summary of contami- 3.1.12 particulate contamination—small discrete mass of
nation accumulation for a given critical hardware item distrib- solid matter, usually measured in micrometers (μm), which
uted over all phases from manufacture through end of perfor- adversely affects component or system performance.
mance lifetime. 3.1.13 precision cleaning—cleaning of hardware surfaces
by approved engineering methods to meet specific cleanliness
3.1.4 cleanroom—an environmentally conditioned area
where temperature, humidity, and airborne contaminants are criteria.
3.1.14 visibly clean—absence of particulate or molecular
controlled by design and operation. High Efficiency Particulate
Air (HEPA) filters or better are usually required to achieve the contaminants when viewed from a specified distance with
air cleanliness level. Air particulate cleanliness is classified in normal (or corrected to normal) vision with a specified
accordance with FED-STD-209. illumination level.
3.1.4.1 as-built cleanroom—a cleanroom that is complete
4. Contents of CCP
and ready for operation, with all services connected and
4.1 General Items and Information:
functional, but without equipment or operating personnel in the
4.1.1 All CCPs shall include an introduction or scope
cleanroom.
specifying the contamination-sensitive component(s) or sys-
3.1.4.2 at-rest cleanroom—a cleanroom that is complete
tem(s) being addressed, a list of applicable documents, and a
and ready for operation, with all services connected and
list of definitions including any acronyms and abbreviations
functional, and with equipment installed and operable, as
used in the document.
specified but without operating personnel in the cleanroom.
4.1.2 The level of detail required and the nature and extent
3.1.4.3 operational cleanroom—a cleanroom in normal op-
of controls needed depends upon a number of factors. The
eration, with all services functioning and with equipment and
systems organization or systems integrator has a better over-
personnel, if applicable, present and performing their normal
view of contamination limitations, sensitivity of specific com-
work functions in the cleanroom.
ponents and hardware, and total mission requirements than
NOTE 2—For batch operations, specific conditions and requirements
sub-tier suppliers. Contamination limits for total systems are
should be noted for monitoring and control.
the primary responsibility of the systems organization. Final
3.1.5 clean zone—a defined space in which the concentra- contamination limits at delivery of the integrated system and at
end of life should be established by agreement between the
tion of airborne particles is controlled to meet a specified
airborne particulate cleanliness class. purchaser and systems supplier. Each supplier is responsible
for defining and controlling the contamination level of the
3.1.6 controlled area—an area which does not require a
high degree of temperature and humidity control but a semi- particular hardware being supplied, with the approval of the
systems organization, in addition to requirements levied by the
clean atmosphere is desired. Air conditioning is standard
systems integrator.
commercial design except that filtration is rated to 80–85 % for
4.1.3 The buyer and seller should agree on the contents and
1.0 micrometer and larger particles to control airborne con-
implementation of the CCP before any parts are processed
taminants. These areas shall not exceed the airborne particle
beyond the first cleaning or inspection point. Suppliers of
concentration of Class M7 (Class 283,000) at 0.5 μm and Class
subsystems and components should prepare Contamination
M6.5 (Class 100,000) at 5.0 μm per FED-STD-209. Reference
Control Plans so that the functional requirements of the
USAF Tech Order 00-25-203.
hardware are protected. If a subsystem is particularly sensitive
3.1.7 facility—the total real property required to accomplish
to contamination, there must be adequate controls and compli-
the environmental control and operation of cleanrooms, clean
ance with system contamination requirements. Examples of
zones, and controlled areas as well as administrative and
sensitive subsystems include optical or non-optical sensors,
personnel support.
gyros, thermal control systems, liquid propellant systems, and
NOTE 3—This includes the cleanroom proper, air locks, change rooms,
cryogenic devices.
parts cleaning, storage, HVAC equipment, offices, etc.
4.1.4 Some subsystems are relatively insensitive to con-
3.1.8 HVAC—Heating, Ventilating, and Air Conditioning.
tamination. These should be identified and justifications given
3.1.9 image analysis—the measurement of size, shape,
for limited contamination control efforts. Even if a particular
number, position, orientation, brightness and other parameters
subsystem or hardware is not sensitive to contamination it must
of small objects using the combination of an autofocusing
not be a source of contamination for other, more sensitive or
microscope, an imaging sensor, and a dedicated computer
critical hardware. Also it is important that system performance
system. Can be used to perform particle counts or measure
or contamination allowables not be degraded by contaminants
particle dimensions automatically, with far greater accuracy
emanating from contamination tolerant hardware.
than manual techniques.
4.2 Cleanliness Requirements:
3.1.10 molecular contamination—nonparticulate matter in 4.2.1 Cleanliness requirements must be specified for deliv-
the form of droplets or thin films which adversely affects
erable components or systems addressing particulate, molecu-
component or system performance. lar, or biological contaminants, or combination thereof. Pri-
3.1.11 nonvolatile residue (NVR)—soluble material remain- mary responsibility for contamination control remains with the
ing after evaporation of a filtered volatile fluid or precipitate hardware or subsystem supplier. Levels of control and allow-
form a gas phase, usually reported in milligrams per unit area able types and quantities of contaminants shall be as agreed by
(or volume). the supplier and systems organization when applicable. Specify
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 1548 – 93 (1998)
contamination limits and the point in time when the require- contaminating operations occur. Preparation for shipment or
ment must be verified (for example, MIL-STD-1246 Level transfer out of the cleanroom should be addressed including
XXX after manufacture, or X.XX % area coverage at delivery type of container, type of packaging, cleaning before packag-
to integration contractor). Define any budget allocations if ing, protective measures, identification of hardware, and veri-
different cleanliness levels are to be verified at different time fication of cleanliness. Materials and processes are critical to
intervals. Also identify whether the requirement is critical to provide effective protection; approved packaging shall be
the hardware performance or is necessary to protect other identified and shall not compromise the cleanliness require-
critical hardware. ments of the critical hardware. The use of inspection seals and
controls plus notation of any precautions or special handling on
4.2.2 Define how the cleanliness requirements will be im-
the packaging shall be described.
posed in operation; identify the relevant documents such as
drawings, process documents, inspection procedures, test 4.4 Environmental Controls—The CCP shall describe the
plans, manufacturing flow diagrams, acceptance plans, etc.
environmental controls that will be utilized for all cleanrooms,
controlled areas, and laminar flow benches to be used, and shall
4.3 Implementation Plan:
include facility maintenance and monitoring schedules.
4.3.1 Attainment of Cleanliness Requirements—Describe
the means for achieving the specified cleanliness requirements. 4.4.1 Facility Design—The actual facility used must be
established and defined. It may be a controlled area, a
This focuses on (1) selection of low outgassing, low shedding,
and low particle generating raw materials, (2) design features cleanroom, a unidirectional flow bench, clean zone, portable
work station, glovebox, etc. Airborne particle concentrations
to protect against contamination such as filters, cold traps,
baffles, debris shields, etc., and (3) cleaning and processing shall be specified per FED-STD-209. The specification shall
state the operating conditions As-built, At-rest, and Opera-
techniques that will effectively remove contaminants from
surfaces. Where prelaunch or post-launch cleaning operations tional. Operational conditions are the most critical for hard-
ware cleanliness. At-rest conditions are indicative of the
are planned, these shall be described here also. These elements
may be contained in separate documents, but shall all be cleanroom performance without personnel. Typical airborne
particle concentrations for Class M4.5 (Class 1,000) through
responsive to the requirements and cross-referenced in the
CCP. Class M6.5 (Class 100,000) and Controlled Areas are specified
at 0.5 μm and 5.0 μm. Typical concentrations for Class M2.5
4.3.2 Verification of Cleanliness Requirements—Identify
(Class 10) to Class M4.5 (Class 1,000) are specified at 0.3 μm
the techniques planned to verify compliance with the cleanli-
and 0.5 μm. Particulate and molecular (NVR) cleanliness levels
ness requirements, including particulate, molecular, or biologi-
on surfaces shall be specified per MIL-STD-1246 or other
cal contaminants, or combination thereof. Rationale for use of
requirement suitable for the hardware being processed.
witness samples versus direct examination or solvent extrac-
tion techniques should be included. Specify method of direct 4.4.1.1 The facility design shall be desc
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