RPT TECHNICAL

STANDARD

RPT Document No.-

RPTSTD-8070-0001

Rev. 3

National Aeronautics and Space Administration Approved: September 2022 Washington, DC 20546-0001 Review Date: September 2027

SURFACE CLEANLINESS STANDARD OF FLUID SYSTEMS

FOR ROCKET ENGINE TEST FACILITIES

OF THE NASA ROCKET PROPULSION TEST PROGRAM

MEASUREMENT SYSTEM IDENTIFICATION:

METRIC (INCH-POUND)

RPT Document No. RPTSTD-8070-0001

DOCUMENT HISTORY LOG

Status Document Revision

Approval Date Description

Basic Basic 10.25.2010 Initial Release, via RPT Program Office

Rev 1 Rev 1 07.02.2012 Minor administrative changes (agreed to in earlier edits) to sections

8.3.2 (remove paragraph c), 14.1 and 14.2 (remove “critical surface areas greater than 0.5m2”), Table 1A (Now reads Level “A” NVR for all oxidizer tanks ≤0.5m2. Level “B” for N2O4 tanks >0.5m2.

Level “E” for O2 tanks >0.5m2) and Table 2, add 100A to Hydraulic. Added Appendix G, Crossover Chart for SSC use only.

Rev 1-1 Rev 1-1 04.30.2013 Administrative change to SSC Crossover Chart: removed “oxidizer” and “oxygen” from *Note at bottom of chart.

Rev 2 Rev 2 05.15.2013 Administrative change to SSC Cross Over chart to clarify NVR requirements. Deleted Note “* Use Level “A” for all Oxidizer lines, parts, components (NVR maximum = 1.0 mg/ 0.1 m2). Use Level “E” for Oxygen tanks > 0.5m2 surface area (NVR maximum = 5.0mg/0.1 m2).” Added “Note 2: Use Level “E” (NVR maximum = 5.0mg/0.1 m2) for tanks > 0.5m2 surface area.”

Rev 2-1 Rev 2-1 03.12.2018 Administrative change to remove note on front cover “This standard has not been reviewed for export control restrictions;

consult your center/facility/headquarters export control procedures/authority prior to distribution of this document.”

Rev 3 Rev 3 07.31.2022 Content update initiated in 2018 but postponed and renewed in 2021 for completion in 2022. 05/15/2018 - Updated to reflect updated standards across the Agency and Industry, as well as best practices.

NOTES:

This document is hosted within the document system of TechDoc, and, is applicable to the RPT Program rocket test sites at NASA SSC, MSFC, JSC-WSTF, and GRC-ATF respectively.

Document may also be copied/archived at multiple sites for ease of accessibility and visibility at all four sites, and notably for the benefit of their respective onsite contractors and customers.

(This document is not controlled by the NASA Agency Level standards program at this time, though it may be considered for this in the future should the need arise).

DOCUMENT ACCEPTANCE AUTHORITY

(Rocket Propulsion Test Sites Only)

NASA Stennis Space Center, Engineering & Test Directorate Harry Ryan, NASA SSC Chief Engineer

NASA Marshall Space Flight Center, Test Laboratory Lisa Bates, Director

NASA JSC/White Sands Test Facility Mary A. Burk, Deputy Manager

NASA Glenn Research Center, Facilities, Test and Manufacturing David Taylor, ATF Deputy Manager

NASA Glenn Research Center David Taylor, Primary RPT Representative

NASA Rocket Propulsion Test Program Christine Powell, Program Manager dheberli Sticky Note This signature block is not needed and will be removed during the next edit.

Thanks, Lynn Heberling

ACKNOWLEDGEMENT

This document has been reviewed by several subject matter experts, including Bartt Hebert, NASA/SSC; Rosella Zapien, NASA/WSTF; Lynn Arrington, Jim Mullens, Lori Arnett, David Taylor, NASA/GRC; Mark Mitchell, Paul Schrader, NASA/MSFC; as well as members of the Rocket Propulsion Test Management Board. Their effort is gratefully acknowledged.

We would like to thank the Core Team Members who were responsible for the update to this document. H. R. Ross, Stennis Space Center, Gas & Materials Science, A2R Corp.;

R. E. Boothe, NASA Marshall Space Flight Center, Component Cleaning, EM22;

C. Y. Pina Arpin, NASA White Sands Test Facility; L. H. Haselmaier, Mississippi Research Consortium/USM; J. E. Doehne, NASA Glenn Research Center; T. T. Gautney, NASA Marshall Space Flight Center, Test Laboratory; C. T. Arnold, NASA Rocket Propulsion Test Program Office, Project Manager.

TABLE OF CONTENTS

SECTION PAGE

1. SCOPE

1.1. Purpose

1.2 Applicability

1.3 Responsibilities

1.3.1 General

1.3.2 Quality Assurance

1.3.3 Safety and Environmental

1.3.4 Training

2. APPLICABLE DOCUMENTS

2.1 General

2.2 Government Documents

2.3 Non-Government Documents

2.4 Order of Precedence

3. ACRONYMS AND DEFINITIONS

3.1 Acronyms and Abbreviations

3.2 Definitions

4. SURFACE CLEANLINESS LEVELS

4.1 Classification

4.2 Non-Precision Cleanliness Levels

4.3 Precision Cleanliness Levels

4.4 Specifying Product Cleanliness Level

4.5 Facility and Fluid System Cleanliness Level Requirements

4.6 Cleanliness of Operational and Legacy Systems

5. SYSTEM CONFIGURATION AND DESIGN

5.1 System Interfaces with Different Cleanliness Levels

5.2 Component Removal

5.3 Bottles and Vessels

5.4 Materials

6. CLEANING

6.1 General

6.2 Decontamination

6.3 Cleaning Process Requirements

6.4 Hardware Processing

6.4.1 Assembled Items

6.4.2 Disassembly Before Cleaning

6.4.3 Critical Surfaces

6.4.4 Pressure Testing

6.4.5 Temporary Hardware

6.4.6 Nonmetallic Items

6.5 Controlled Area

6.6 Rough Cleaning

6.6.1 Exceptions

6.6.2 Mechanical Cleaning

6.6.3 Chemical Cleaning

6.6.4 Acid Cleaners

6.6.5 Alkaline Cleaners

6.6.6 Degreasers (Organic and Aqueous-Based Solvents)

6.6.7 Caustic Cleaners

6.7 Precision Cleaning

6.8 Field Cleaning

6.8.1 Preparation Before Field Cleaning

6.8.2 Decontamination

6.8.3 System Considerations

6.8.4 Installation of Temporary Hardware

6.8.5 Pressure Tests

6.8.6 Cleaning/Verification

6.8.7 Field Certification

6.8.8 Controlled Area Exceptions

6.8.9 Post-Verification Operations

6.8.10 Post-Verification Inspection

6.8.11 Protection of Cleaned Systems/Items

6.9 Excepted Components/Items

6.10 Equivalent Cleaned Items

7.0 CLEANING FLUIDS, VERIFICATION FLUIDS, AND RINSING AGENTS

7.1 General

7.2 Compatibility

7.3 Approved Halogenated Solvents for Precision Cleaning

7.3.1 Trichlorotrifluoroethane (CFC-113)

7.3.2 HCFC-225g (AK-225g)

7.3.3 HCFC-225 ca/cb (AK-225)

7.3.4 1,1,1 Trichloroethane (Methyl Chloroform)

7.3.5 Tetrachloroethylene (Perchloroethylene)

7.3.6 Trichloroethylene

7.3.7 Methoxynonafluorobutane (Hydrofluoroether-7100, HFE-7100®)

7.3.8 Decafluoropentane 62% & Trans-1,2-Dichloroethylene 38% (Vertrel MCA®) ...42

7.3.9 Decafluoropentane (HFC-4310 mee or Vertrel XF®)

7.3.10 Trans-1-Chloro-3,3,3-triflluropene (Solstice PF or PF-HP)

7.4 Alcohol Solvents

7.4.1 Isopropyl Alcohol

7.4.2 Ethyl Alcohol

7.5 DI Water

7.5.1 DI Water Verification Reagent (Used for Cleanliness Verification)

7.5.2 DI Water Rinsing Agent

7.5.3 Hydraulic Fluids for Cleanliness Verification

8. FLUID CONTROL REQUIREMENTS

8.1 Solvent Control Samples

8.2 Solvent Verification (Test) Samples

8.3 Solvent Volume Required For Cleanliness Verification

8.3.1 Items with Surface Area Less Than 0.1m2

8.3.2 Items with Surface Area Between 0.1 and 0.5m2

8.3.3 Components/Items With Surface Area Greater Than 0.5m2

9. VISUAL CLEANING CERTIFICATION

9.1 Visual Cleanliness

9.2 Flash Rust

9.3 Inspection Aids

9.4 UV Cleanliness Level

10. QUANTITATIVE CLEANLINESS CERTIFICATION

10.1 Method I – Component/ /Item Flush with Non-Halogenated Solvents or DI

Verification Reagent

10.2 Method II – Component or Item Flush with Halogenated Solvent

10.3 Method III – NVR Using DI Water Verification Reagent

10.4 Method IV – NVR and Particle Determination for Fluid Transmission Lines

10.5 Method V – Flow Through Item By Gas

10.6 Method VI – Solvent Flow-Through Method

10.7 Method VII – Wipe Samples from Representative Critical Surface Area

10.8 Method VIII – Hydraulic Fluid Flush for Particulate Verification

11. ACIDITY AND ALKALINITY TEST

12. GAS REQUIREMENTS

13. SOLVENT REMOVAL VERIFICATION

13.1 Process Control - Performance Equivalent for Solvent Removal

13.2 Gas Sample

14. DRYNESS VERIFICATION (MOISTURE REMOVAL)

14.1 Purge Method

14.2 Static Pressurization Method

14.3 Bakeout

14.3.1 Process Control – Performance Equivalents for Moisture Removal (Dew

Point)

14.3.2 Thermal -Vacuum Bakeout

14.3.3 Ambient Pressure Bakeout

15. PROTECTION AND PACKAGING OF CLEANED ITEMS

15.1 General

15.2 Packaging Films

15.3 Metallic Closures

15.4 Protective Devices

15.5 Dessicants

15.6 Inert Gas Purging

15.7 Sealing

15.8 Detailed Requirements

15.8.1 Small Items

15.8.2 Items Internally Cleaned Only

15.8.3 Items with Flange or Hub Nozzle Connections

15.8.4 Electrical and Electronic Items

15.8.5 Hose and Tube Assemblies

15.8.6 Identification of Cleaned Items

15.8.7 Packaging Removal

16. RECORDS AND FORMS

Appendix A SOLVENT REQUIREMENTS Appendix B TEST METHODS Appendix C CLEANLINESS VERIFICATION USING THE TEST SPOOL METHOD Appendix D METHOD V, NVR AND PARTICLE DETERMINATION FOR IN

SERVICE SYSTEMS

Appendix E METHOD VII, WIPE SAMPLES FROM REPRESENTATIVE CRITICAL

SURFACES

Appendix F THERMAL VACUUM DRYING TIME (HOURS) Appendix G CROSSOVER CHART, FOR SSC USE ONLY

LIST OF FIGURES

FIGURE PAGE

Figure D–1. Gas Sampler for NVR Residue

LIST OF TABLES

TABLE PAGE

Table 1. Fluid surface cleanliness levels Table 2. Surface Cleanliness Requirements Table 3. Quantitative cleanliness verification methods Table 4. Packaging Materials Thickness and Service Requirements

Table A–1. Trichlorotrifluoroethane Table A–2. HCFC-225G Table A–3. HCFC-225 Table A–4. HFE-7100 Table A–5. Vertrel MCA Table A–6. Vertrel XF Table A–7. Solstice PF or PF-HP Table B–1. QC Requirements Table D–1. Sampling Time

Surface Cleanliness Standard of Fluid Systems for Rocket Engine Test Facilities

1. SCOPE

1.1. Purpose

The purpose of this standard (STD) is to specify the cleanliness levels and the minimum contamination control requirements (processing, handling, protection, and test/inspection) for surfaces that come in contact with any fluid medium. These requirements pertain to the “critical surfaces” of parts, items, components, equipment, assemblies, subsystems, and systems used for NASA’s rocket propulsion test program.

1.2 Applicability

a. This standard is applicable to ground-based rocket propulsion test facilities for propellant, pressurant, pneumatic, and hydraulic systems that require cleanliness certification.

Specifically, these are the test stands and facilities under the purview of the NASA Rocket Propulsion Test (RPT) Program.

b. All system and product cleanliness levels shall meet or exceed program or test article requirements. Program- or customer-specified requirements may impose additional cleanliness or process requirements. In such situations, process changes and supplemental procedures may be required to satisfy any additional program- or customer-specified requests.

c. This standard may be cited in contract, program, and other Agency documents as a technical requirement.

d. Mandatory requirements are indicated by the word “shall.”

e. Tailoring of this standard for application to a specific program or project shall be approved by the Technical Authority for that program or project.

f. Waiver decisions may be subject to requirements for the acceptance of risks to safety and mission success in NPR 8000.4. Any requirements within this document shall follow the respective Center’s approved processes in waiving technical requirements. Any such waiver may be accompanied by engineering assessments, MRB reviews, with notification to the Rocket Propulsion Test Program Office (RPTPO).

g. The RPT Program Manager may grant a temporary or permanent exclusion from this standard to a specific RPT facility or element when it is deemed to be in the best interest of the Agency’s Rocket Propulsion Test capability. Center requests for exclusions shall be presented to the RPTMB, with supporting rationale and documentation. Exclusions shall be documented in a Program Directive, along with any limitations or conditions associated with the exclusion.

1.3 Responsibilities

1.3.1 General

a. NASA and contractor personnel responsible for engineering design, manufacture/fabrication, propulsion test operations, cleaning and inspection, calibration, and analysis activities shall implement this STD.

b. NASA and the Contractor shall ensure compliance with requirements of this STD through surveillance, auditing, and process verification.

c. Design specifications and drawings shall identify cleanliness levels by the alphanumeric or numeric designations defined in this STD.

d. The user is responsible for assuring suitability of the cleaned item for its intended use.

1.3.2 Quality Assurance

The performing organization’s quality assurance (QA) shall review and verify that the surface cleanliness requirements for fluid systems are satisfied.

1.3.3 Safety and Environmental

a. All users of this standard must review pertinent Safety Data Sheet (SDS) specifications and work instructions to assure safety of personnel and protection of the environment and facilities in fulfilling the requirements of this STD.

b. All materials and processes required to fulfill the requirements of this STD are subject to applicable Federal, State, and local environmental, health, and safety regulations, standards, codes, and operating procedures (e.g., work instructions). The performing organization is responsible for determining and establishing the appropriate environmental, health, and safety practices that comply with all applicable regulations.

c. Questions regarding these activities, including air emissions, spills, solid and hazardous waste inventory, storage, removal, disposal, discharges, and waste minimization (e.g., recycling) shall be referred to the cognizant personnel within the performing organization.

1.3.4 Training

a. The performing organization or contractor shall assure that all personnel responsible for contamination control functions are trained as required to assure proficiency within their assigned tasks.

b. The processing organization or contractor shall establish personnel certification with traceable documentation.

2. APPLICABLE DOCUMENTS

2.1 General

a. The documents listed in this section contain provisions that constitute requirements of this standard as cited in the text of Section 4.

b. The latest issuances of cited documents shall be used unless otherwise approved by the assigned Technical Authority. The applicable documents are accessible via the NASA Technical Standards System at http://standards.nasa.gov, directly from the Standards Developing Organizations, or from other document distributors.

2.2 Government Documents

Federal Specification A-A-1689 Tape, Pressure-Sensitive Adhesive (Plastic Film)

A-A-59150 Cleaning Compound, Solvent, Hydrofluoroether (HFE)

A-A-3174 Plastic Sheet, Polyolefin

A-A-59503 Nitrogen, Technical

TT-I-735 Isopropyl Alcohol

Military Specifications and Handbooks MIL-C-81302 Cleaning, Compound, Solvent, Trichlorotrifluoroethane

MIL-T-81533 Trichloroethane 1,1,1, (Methyl Chloroform) Inhibited, Vapor

Degreasing

MIL-STD-889 Dissimilar Metals

MIL-HDBK-1028/5A Environmental Control – Design of Clean Rooms

MIL-PRF-27401 Propellant Pressurizing Agent, Nitrogen

MIL-PRF-27407 Propellant Pressurizing Agent, Helium

MIL-PRF-5606 Hydraulic Fluid, Petroleum Base; Aircraft, Missile, and Ordnance

National Aeronautics and Space Administration

JSC-SPEC-C-20 Water, High Purity, Specification for http://standards.nasa.gov/

MSFC-SPEC-3709 Solvent, Cleaning, Trans-1-Chloro-3,3,3,-Trifluoropropene, Solstice® PF, Specification for

MSFC-STD-3535 Standard for Propellants and Pressurants used for Test and Test

Support Activities at SSC and MSFC

KSC SPEC-P-0019 Solvent, Cleaning, 1,1,1,2,3,4,4,5,5,5 – Decafluoropentane (62 wt%) and Trans-1,2 – Dichloroethylene (38 wt%), Vertrel MCA, Specification for

KSC SPEC-P-0021 Solvent, Cleaning, 1,1,1,2,3,4,4,5,5,5 – Decafluoropentane, Specification for

KSC SPEC-P-0022 Solvent, Cleaning, 1,3-Dichloro-1,1,2,2,3, - Pentafluoropropane, Specification for

NASA STD 6001 Flammability, Odor, Off-gassing and Compatibility Requirements and Test Procedures for Materials in Environments that Support Combustion

NASA /TP 2015- NASA Precision Cleaning Agent Solstice 218207

2.3 Non-Government Documents

American Chemical Society (ACS) Reagent Chemicals: Specifications and Procedures

American Society for Testing and Materials (ASTM) ASTM A 380 Standard Practice for Cleaning, Descaling, and Passivation of

Stainless Steel Parts, Equipment, and Systems

ASTM D 1193 Standard Specification for Reagent Water

ASTM D 4080 Standard Specification for Trichloroethylene, Technical and Vapor

Degreasing Grade

ASTM D 4376 Standard Specification for Vapor-Degreasing Grade

Perchloroethylene

ASTM D 5486 Standard Specification for Pressure-Sensitive Tape for Packaging, Box Closure, and Sealing

ASTM E 2042 Standard Practices for Cleanliness and Maintaining Controlled

Areas and Clean Rooms

ASTM F 312 Standard Test Methods for Microscopical Sizing and Counting Particles from Aerospace Fluids on Membrane Filters

ASTM F 331 Standard Test Method for Nonvolatile Residues of Solvent Extract from Aerospace Components (Using Flash Evaporator)

ASTM G 144 TOC NVR Method Reference

Compressed Gas Association (CGA) CGA G-11.1 Commodity Specification for Argon

International Organization for Standardization ISO 14644-1 Cleanrooms and Associated Environments – Part 1, Classification of Air Cleanliness

ISO 14644-2 Cleanrooms and Associated Controlled Environments – Part 2, Specifications for Testing and Monitoring To Prove Continued Compliance with ISO 14644-1

Society of Automotive Engineers (SAE) Aerospace Material Specifications (AMS) SAE-AMS 3647 Polyfluoroethylene Propylene Film and Sheet

SAE-AMS 3649 Film, Polychlorotrifluoroethylene (PCTFE) Unplasticized

General Industry IEST-STD-CC1246 Product Cleanliness Levels and Contamination Control Program

Society of Automotive Engineers (SAE) Aerospace Recommended Practices (ARP) SAE-ARP 598 Aerospace Microscopic Sizing and Counting of Particulate

Contamination for Fluid Power Systems

2.4 Order of Precedence

When this standard is applied as a requirement or imposed by contract on a program or project, the technical requirements of this standard take precedence, in the case of conflict, over the technical requirements cited in applicable documents or referenced guidance documents.

3. ACRONYMS AND DEFINITIONS

3.1 Acronyms and Abbreviations

AMS Aerospace Materials Specification AM&TE Analytical Measurement and Test Equipment ARP Aerospace Recommended Practices ASTM American Society for Testing and Material CGA Compressed Gas Association CS Control Sample (Solvent Blank NVR) DI Deionized EXC Excepted FEP Polyfluoroethylenepropylene FTIR Fourier Transform Infrared GC Generally Clean GH Gaseous Hydrogen GOX Gaseous Oxygen HFE Hydrofluoroether IM&TE Inspection, Measuring and Test Equipment IR Infrared ISO International Organization for Standardization JSC Johnson Space Center KSC Kennedy Space Center LH Liquid Hydrogen LOX Liquid Oxygen MMH Monomethyl hydrazine mg milligram mL milliliters MS Measured Sample NVR concentration MSFC Marshall Space Flight Center MIL Military NASA National Aeronautics and Space Administration NVR Nonvolatile Residue N2H4 Hydrazine N2O4 Dinitrogen Tetroxide PCTFE (TFE) Polychlorotrifluoroethylene PFEP (FEP) Polyfluoroethylene-propylene ppm parts per million PVC Polyvinyl Chloride QA Quality Assurance RPT Rocket Propulsion Test (Program Office) SA Surface Area SAE Society of Automotive Engineers scf standard cubic feet SDS Safety Data Sheet SF Sensitivity Factor

SPEC Specification SSC Stennis Space Center STD Standard TCA Total Carbon Analyzer TOC Total Organic Carbon UDMH Unsymmetrical dimethyl hydrazine UV Visually Clean Plus Ultraviolet (ultraviolet cleanliness level) VC Visually Clean WSTF Johnson Space Center’s White Sands Test Facility

3.2 Definitions

Analytical Measurement and Test Equipment (AM&TE): equipment used by a Science or analytical testing laboratory (e.g., IR spectrometer, gas chromatograph, scanning electron microscope, etc.). AM&TE analysis data is controlled by verification or standardization processes using chemical reference materials and/or standardized protocols (ASTM, ISO, EPA).

Assembly: two or more parts having a common mounting and being capable of performing a definite function. For example, filter element, housing, and O-ring become part of a filter assembly.

Black Light: a high intensity, long-wave, low-energy, ultraviolet (UV) light operating from 3200- 3800 angstroms wavelength range.

Blank: the analytical result that describes the particulate or NVR background level of the certified test fluid before use in performing a cleanliness verification test.

Blanket Purge: the use of pressurized gas in an enclosed environment for protecting components, piping, or vessels from contamination.

Certification: a written record demonstrating that requirements have been verified and achieved.

Cleaning: the removal of incompatible materials from the significant surfaces of components and systems within the scope of this standard.

Clean Room: a room within which the concentration of airborne particles is controlled and classified, and which is designed, constructed and operated in a manner to control the introduction, generation and retention of particles inside the rooms, as referenced in ISO 1466.1.

Clean Zone: defined space within which the number concentration of airborne particles is controlled and classified, and which is constructed and operated in a manner to control the introduction, generation and retention of contaminants inside the space (e.g., laminar flow bench).

Commercial Clean: also known as visually cleaned (VC).

Component: an item that is normally a combination of parts, subassemblies, or assemblies and that is self-contained within a fluid system.

Contaminant: any material that could chemically react or mechanically interfere with a cleaned component, system, or end item.

Control Sample: a specific volume of flushing solvent that is analyzed to determine a baseline contamination level before a test or verification sample is attained. A control sample and a blank are considered to be equivalent.

Critical Surface: a surface that may come into contact with the fluid (service) medium (i.e., liquid oxygen, pneumatic gases, hydraulic fluids, etc.). A critical surface is subject to the cleaning procedures and cleanliness requirements of this specification.

Dew Point: the temperature at which a gas becomes saturated with water vapor and condensation begins (usually atmospheric pressure).

Drying: reducing moisture or dew point levels by vacuum, purge, flush, or oven-heated methods.

Excepted Component/System/Soft Good: an item or system that cannot be cleaned and certified using normal procedures or facilities because of their size, construction, or method of assembly.

Fiber: a non-metallic structure having a length-to-width ratio of 10 to 1 or greater with a minimum length of 100 micrometers (A fiber is a particle).

Field Certification: the process of certifying components in the field.

Field Cleaning: cleaning performed outside a shop or clean environment.

Field Verification: process of obtaining samples in the field for subsequent laboratory analysis to certify cleanliness levels.

Fluid: a gas or liquid.

Flushing Solvent: the solvent used to obtain the control sample and the test sample.

Foreign Object Debris (FOD): a substance, debris or article that is alien or has invaded a product, assembly, or system, and would potentially cause damage. Examples are tools, un-attached tape, metallic chips, wire clippings, loose tie-wraps, and loose hardware such as washers, nuts, and screws.

Footcandle: measures the number of lumens per area of one square foot.

Generally Clean (GC): inspection is not as rigorous as visually clean (VC) in that clumps or agglomerations of contamination are removed instead of individual particles. Cleaning is only required if the item does not pass inspection. If the item has been inspected and accepted “as is,” it does not need to be cleaned. Heat-sealed bagging protection is not required, but normal protection is required for handling, shipping, and storage. This cleanliness level should be specified for hardware that is not sensitive to contamination and is easily cleaned.

Gross Cleaning: the removal of gross contaminants, also known as rough cleaning.

Gross Contaminants: visible contaminants, such as moisture, corrosion, loose slag, oil, grease, scale, rust, soil, sludge, and grit.

Hydrocarbon: any compound containing carbon and hydrogen bonds.

Hypergolic Propellants: any fuel/catalyst (monopropellant) or fuel/oxidizer (bipropellant) combination that spontaneously ignites and is used in propelling a rocket.

Inaccessible: unable to be viewed because of physical configuration.

Inspection: the verification method performed by visual observation under ambient or black light.

Inspection, Measuring and Test Equipment (IM&TE): instrument measurement and test equipment that are calibrated by a calibration laboratory (e.g., pressure gages, flow meters, balances, volt meters, etc.) and are used to perform measurements where distinct values are required for system performance or to demonstrate conformance to specified requirements.

Item: anything smaller than or contained within a system (e.g., assembly, component, IM&TE, piece part).

Method: a technique or process used to test, inspect, or collect samples.

Micron: dimension of length equal to 10-6 m or 0.001 mm (0.0000394 inch).

Moisture: the residual water (liquid/gas) on components or systems, measured in ppm or dew point.

Nonvolatile Residue (NVR): the residue remaining after filtration and controlled evaporation of the final flushing solvent. NVR is specified in mg per square meter or square foot of significant surface. Since the predominant constituents of NVR are typically hydrocarbons, NVR and total hydrocarbon content are considered equivalent. Analytical methods that determine total hydrocarbon (Fourier Transform Infrared (FTIR), and total organic carbon (TOC) and gravimetric NVR, as referenced in ASTM F331 may be used to determine NVR.

Normalize: describe (convert or calculate) a measurement (e.g., NVR weight or particle count) per specified unit area (or volume). Example: A NVR of 0 .6 mg / was obtained from a significant surface area of 0.5 ft

2 equals 1.2 mg/ft 2 of NVR .

Oxidizer: commodities, such as liquid oxygen and nitrogen tetroxide, which when combined with fuels (liquid hydrogen and hydrazine respectively), constitute the propellants for rocket engines.

Air is also considered an oxidizer.

Oxygen System: a system containing a fluid with more than 25 mole percent oxygen. Air (20.94 mole percent oxygen) at pressures exceeding 2000 psig can react like pure oxygen at the same pressure. Air under these conditions will be treated like an oxidizer.

Packaging, Primary (or Primary Packaging Film): material (or film material) used to prevent contaminant entry onto precision cleaned items or precision cleaned (critical) surfaces. This material is either used to fabricate bags that totally enclose precision cleaned item(s) or stretched across and wrapped around openings or orifices of items with internal critical or precision cleaned surfaces, This material provides limited physical protection to surfaces covered by this type of packaging, but this material is never to be the sole means/provider of this protection.

Packaging, Secondary (or Secondary Packaging Film): material (or film material) used to prevent visible contaminant entry onto the primary packaging (film). In selected cases where precision cleaned items are enclosed in bags in conjunction with protective external overwrap or containers or where covered openings of these items are small, this material provides physical protection to prevent damage to the primary packaging (film) and surfaces covered by this packaging. However, in most cases or for larger openings covered by packaging films, added protective devices are required to protect secondary packaging from damage or puncture.

Particle: a unit of matter with observable length, width, and thickness; usually measured in micrometers (microns). Particle size is measured in the longest dimension (e.g., fibril, fiber, filament, powder, soot, dirt, dust, mineral oxides, metallics, ceramics, any particulate matter).

Particulate: multiple particles.

Passivation: the process by which a chemically inert layer ( e.g., chromium oxide) is formed on a metal surface by submersing the surface in a chemical solution (e.g., nitric acid, hydrogen peroxide, etc.).

pH: a unit of measure that describes the acidity or alkalinity of an aqueous solution on a scale of 0 to 14 (a pH of 7 is neutral, a pH value below 7 is acidic, a pH value above 7 is alkaline). pH is the logarithm of the reciprocal of the hydrogen ion concentration of a solution.

Pickling: the chemical or electrochemical process by which surface oxides are removed from metals.

Performing Organization: the onsite or offsite organization performing the cleaning or cleanliness verification services.

Precision Clean: a detailed cleaning process that requires quantitative verification such as an NVR and /or particulate measurement, used to achieve cleanliness levels more stringent than visually clean.

Procuring Organization: the organization authorized to issue the procurement of goods and services (e.g., cleaning or cleanliness verification services.)

Rough Cleaning: a pre-cleaning or gross cleaning process normally used to remove gross contamination. Cleaning operations performed prior to proceeding to precision cleaning.

Sample: a selected portion or quantity of fluid collected to determine the cleanliness level of a system or component.

Significant Surfaces: any surface of a component, item, assembly, subsystem, system, and ground support equipment that comes into contact with test fluids or service/medium fluid (liquid oxygen, pneumatic gases). A significant surface is subject to the cleaning procedures and cleanliness requirements of this Standard.

Silting: an accumulation of particles below the size ranges counted and in such a quantity as to interfere with sample analysis (i.e., to cause a haze or to obscure any portion of a grid line or any portion of the grid of a filter membrane when viewed visually or under magnification).

Soft Good: polymer or polymer-containing materials that are used for integral parts of a fluid system. Ceramics are not included in the term "soft goods." Soft goods are often referred to as "nonmetals."

Test: the process used to determine the cleanliness level of a system, component, or packing material.

Test Sample: a specific volume of flushing solvent used for particulate and/or NVR analysis.

Visual Clean (VC): the absence of all particulate and non-particulate matter visible to the normal unaided (except corrected vision) eye with an illumination equal to or greater than 50 foot candles.

Ultraviolet (UV) Clean: visually clean and inspected with the aid of an ultraviolet light of 3200 to 3800 angstroms. This level requires precision cleaning methods but no particle count.

Verification: the process whereby one or more of the following methods is used for the purpose of certification: performing visual inspections, obtaining samples, analyzing/testing samples, and reviewing inspection/test data.

4. SURFACE CLEANLINESS LEVELS

4.1 Classification

Cleanliness levels imposed by this standard are listed in Table 1.

4.2 Non-Precision Cleanliness Levels

a. Generally Clean (GC):

1. Freedom from manufacturing residue, dirt, oil, grease, scale, carbon deposits, process debris, or other extraneous contamination. This level can be achieved by washing, brushing, or rinsing.

2. The GC level shall not be designated for items or fluid systems that are sensitive to contamination.

3. GC is the only cleanliness level that does not require items to be packaged. Gloves or forceps are not required for the handling of GC items.

b. Visibly Clean (VC): The absence of all particulate and non-particulate matter visible to the normal unaided (except corrected vision) eye. Particulate is identified as matter of size with observable length, width, and/or thickness. Non-particulate matter is a film or residue without definite dimension. Scale-free discoloration due to surface treatments (i.e., passivation, anodizing, etching, etc.) or thermal processes (i.e., welding, heat treatments, etc.) is permitted. Rough cleaning is the process normally used to achieve this cleanliness level. Level VC is commonly referred to as “commercially clean.” Visibly Clean(VC) lighting requires an illumination of > 50 foot candles.

4.3 Precision Cleanliness Levels

a. UV: Visibly clean (as defined above) and inspected with the aid of an ultraviolet light (black light) of 3200 to 3800 Angstroms. This level requires precision cleaning methods.

b. Any visible contamination or fluorescence shall be cause for re-cleaning.

c. If re-cleaning does not reduce fluorescence, an investigation shall be made to determine whether the fluorescing material is contamination or if the item material is naturally fluorescent.

d. Some acceptable materials may fluoresce (e.g., anodized or chemical films). Inspection under ultraviolet light will not detect all vegetable, animal, and fluorocarbon type oils and greases, (e.g., RP-1, JP-5, kerosene, mineral oil, toluene, DC-11®, Krytox® oil, or hydraulic fluid such as MIL-PRF-5606).

e. Level 1000 is the lowest precision cleaning level that requires a fluid sample for cleanliness certification (quantitative particulate count).

Table 1. Fluid Surface Cleanliness Levels (Table 1A)

Particulate Matter Contamination Levels

(Table 1B) NVR Contamination

Levels

(Table 1C) Visible Contamination Levels

Level Particle

Size Range µ (micrometer)

Maximum Number of Particles per

0.1 m2

Level Maximum NVR

(mg. per 0.1 m2) Level Definition

25 <5 5 to 15 >15 to 25 >25

Unlimited *

A 1.0 GC Freedom from manufacturing residue, dirt, oil, grease, etc.

− Level GC is similar to level VC but differs in the following significant areas:

• Cleaning is only required if the item does not pass inspection. If the item has been inspected and accepted “as is,” it does not need to be cleaned.

• Inspection is not as rigorous as VC in that clumps or agglomerations of contamination are removed instead of individual particles.

• Heat-sealed bagging protection is not required, but normal protection is required for handling shipping, and storage.

The GC level should be specified for hardware that is not sensitive to contamination and is easily and quickly cleaned or re-cleaned.

50 <15 15 to 25 >25 to 50 >50

Unlimited *

B 2.0 VC The absence of all particulate and non-particulate matter visible to the normal unaided eye or corrected-vision eye; commercially cleaned.

100 <25 25 to 50 >50 to 100 >100

Unlimited *

C 3.0 UV Visually clean and inspected with ultraviolet light; requires precision cleaning methods

150 <50 50 to 100 >100 to 150 >150

Unlimited *

D 4.0 ● NVR & Moisture Requirements Critical surfaces with NVR requirements will meet:

Level “A” NVR for all oxidizer tanks ≤0.5m2.

Level “B” for N2O4 tanks >0.5m2. Level “E” for O2 tanks >0.5m2.

Moisture Removal Verification by Process Control OR by Lab Test (per section 14.3):

One method of drying small parts in an oven is specified in par. 14.3 Another technique is drying/purging with ultra-high purity nitrogen per MIL- PRF-27401 or MSFC 3535. The choice of method is based on the physical features of the part per 14 or the customer’s requirements.

200 <50 50 to 100 >100 to 200 >200

Unlimited *

E 5.0

250 <100 100 to 200 >200 to 250 >250

Unlimited *

F 7.0

300 <100 100 to 250 >250 to 300 >300

Unlimited *

G 10.0

400 <100 100 to 250 >250 to 400 >400

Unlimited *

UV Non-quantitative NVR detection.

● Dew point & Moisture Content -54° C (-65 °F) 24 ppm for lines, parts, and components -40 °C (-40 °F) 128 ppm for tanks and vessels Dew point & moisture is not required if the critical surface is normally opened to the atmosphere or if the critical surface is exposed to moisture during normal operations

● NOTES

Allowable particulate and NVR are based on 0.1 m2 (1.08 ft2)

* Silting is not permitted

500 <100 100 to 250 >250 to 500 >500

Unlimited *

750 <250 250 to 500 >500 to 750 >750

Unlimited

1000 <500 500 to 750 >750 to 1000 >1000

Unlimited

Notes for Tables 1A & 1B

1. If specified in work documents or engineering drawings, a gas sample for dew point and moisture is not required if the critical surface is exposed to moisture during normal and routine operations, or opened to the atmosphere (e.g., dump or vent lines), or the critical surfaces will come in contact with moisture during normal operation.

2. For such cases, the component cleanliness level shall be indicated as xxx-NDP (No Dew Point) requirement shall be appended to the cleanliness level indication. However, the presence of visible moisture is not permitted for cleanliness level VC or for any precision cleanliness level.

4.4 Specifying Product Cleanliness Level

Product cleanliness levels shall be determined by program and system requirements, which shall be specified as in the following examples:

a. Level 300 refers to size and count limits on particulate contamination only.

b. Level A refers to Nonvolatile Residue (NVR) limits only (i.e., 1 mg/0.1 m2).

c. Level 300A refers to (1) particulate size ranges and counts, and (2) NVR.

d. Level 200A is a more stringent cleaning level than 200B.

e. Level 750A NDP is the same cleanliness level as 750A except the dew point and moisture requirement is absent for the NDP designation (not required).

Table 1 - Visible Contamination Levels (Cont.)

f. A component cleaned to a more stringent cleanliness level than is required for a system application may be used in the system application (e.g., an item cleaned to level 100A) and may be used in a product or system requiring less stringent cleanliness level (e.g., level 200 or 200A or UV).

g. Level VC is a more stringent cleaning level than GC.

h. No particulate count is required for any visual cleanliness level (GC, VC, or UV).

4.5 Facility and Fluid System Cleanliness Level Requirements

a. Table 2 provides a practical range of cleanliness levels for facility fluid systems.

b. System and product cleanliness levels shall meet or exceed program or test article requirements.

c. The precision cleanliness levels in Table 1A require quantitative tests as specified in

Section 10 and conformance to visual cleanliness requirements and inspection (Section 4.2 (b).

4.6 Cleanliness of Operational and Legacy Systems

a. Fluid surfaces of any operational or legacy systems that were not previously cleaned or were not maintained clean (exposed to environments or conditions that degraded the cleanliness beyond the specified cleanliness requirement) or is suspected not to comply with this standard shall be sampled and analyzed to verify the cleanliness level. If the cleanliness level is not adequate, the system shall be recleaned and recertified.

b. NVR and /or particulate sampling of precision cleaned surfaces shall be representative of all surfaces; including varying substrate material/s, and surface types. The cleaning organization shall identify and sample the component or areas most likely to accumulate contaminants due to configuration, location, and other technical considerations. Liquid samples shall be processed for NVR and/or particulate, whether the sample is a liquid itself, a flush-rinse sample, an immersion sample, or from an extracted NVR wipe.

c. Documentation, including all applicable data, shall be recorded and maintained that demonstrates acceptable cleaning processes and cleanliness verifications have been performed. This applies to all parts, components, assemblies, and associated equipment for use in oxygen, pressurizing fluids, pneumatic, fuel and hydraulic systems. Subsequent handling of all hardware /components during assembly, removal, testing or maintenance operations shall be conducted to maintain the acceptable level of cleanliness per the requirements of this standard.

d. Documented procedures for contamination control (requires approval by the responsible organizations’ engineering and management) shall be developed to maintain the cleanliness of clean systems, equipment and components. The procedure shall ensure all known contamination concerns and risks are identified and communicated in a common way across each center / site that adversely impacts cleanliness or test performance. For example, if system entry must be performed during adverse weather conditions, temporary protection (wind breaks, weather shields) shall be provided. Another example, when test hardware or facility system is disconnected, disassembled, uncovered, or the integrity of the closed systems is interrupted or disturbed, care should be exercised to prevent the introduction of contamination. Never perform any unnecessary task over an open port of a clean system.

e. Qualification testing of fluids (propellants, pressurizing agents, and hydraulic fluids) introduced into the cleaned systems shall meet the applicable procurement requirements specified by the test program or engineering work instructions. Subsequent handling of all commodities during storage, offloading from bulk sources, transfers and maintenance shall be conducted to maintain the acceptable level of cleanliness per the requirements of this standard.

Table 2. Surface Cleanliness Requirements Fluid System Facility Item Description Cleanliness Level①③④

LOX/GOX Metallic and/or PTFE components 400A LOX/GOX Nonmetallic parts and components (except PTFE ) VC LOX/GOX Metallic Tanks or vessels 750E

LOX Emergency dump/vent system(s) UV NDP LH/GH/ CH4 Metallic and/or PTFE parts and components 400 LH / GH/ CH4 Nonmetallic parts and components (except PTFE) VC LH /GH / CH4 Tanks or vessels 400 LH /GH / CH4 Vent and flare stacks VC NDP H2O2 / N204 Metallic or virgin PTFE parts and components 400A ② H2O2 / N204 Nonmetallic parts and components (except PTFE④) VC ② H2O2 / N204 Metallic Tanks or vessels 400C ②

Alcohols All items 100 Hydrocarbon Fuels, less Methane (CH4) All items 400

MMH /UDMH All items depending on connecting service 200 to 300 N2H4 All items depending on connecting service 200 to 300

He / HPA Metallic or PTFE items depending on connected service

100A 400A or 750A or 1000A

He / HPA Nonmetallic parts and components (except PTFE④) depending on connected service

VC

He Vent or area purge VC NDP GN2 / LN2 Depending on connected service 100A 400A 750A or 1000A

GN2 LH barges 1000 Hydraulic All items 100 or 100A

NOTES:

Propulsion systems containing hypergols or oxygen may require cleanliness levels more stringent than those defined in Table 2 for system performance or safety. Oxygen systems in particular require a detailed understanding of the potential hazard prior to selecting the appropriate cleanliness level.

When more stringent cleanliness levels than those shown in Table 2 are required, they shall be specified on the engineering drawing or specification in accordance with (or tailored from) IEST-STD- CC1246 with cleaning, inspection, and packaging in accordance with this document.

① Depending on the site specific requirements, more stringent cleanliness levels are acceptable. A filter with an appropriate absolute rating shall be used where particulate facility system cleanliness levels are less stringent than the test article requirements.

② Critical surfaces for H202 or for any item requiring passivation shall be passivated after rough cleaning and before performing final cleanliness verification.

③ Multiple service parts shall be cleaned to the most restrictive requirements.

④ Used in small quantities for cleanliness verification only. Under no circumstances shall PTFE be left to soak in halogenated solvents for extended periods due to the risk of swelling.

For systems, subsystems and components where cleanliness levels differ as shown above, Process and Instrumentation Diagram (P&ID) or engineering drawings or requirements shall indicate cleanliness levels.

5. SYSTEM CONFIGURATION AND DESIGN

The consideration of contamination control during the design phase or during system modifications is of the utmost importance. To assure the most effective contamination control, the engineering design or modification shall provide for:

a. Features that minimize or eliminate self-generating contamination.

b. Materials compatibility for contamination and corrosion control.

c. Features to facilitate contamination removal and monitoring during maintenance (items that would entrap fluids - e.g., reduce or eliminate component configurations with dead end volumes or hardware with complex physical configuration). Proper design consideration will minimize un-drainable cavities, blind holes, pockets, and other areas in which dirt and cleaning solutions might become trapped and would not provide for effective circulation and removal.

a. Incorporation of filtration and/or other control features to reduce contamination during system operation.

b. Lubricants, sealing and staking compounds, nonmetallic materials, etc., shall be selected, tested, and controlled to ensure preservation of the required cleanliness levels.

c. Selection and evaluation of these materials shall include consideration of outgassing and degradation resulting from operational and environmental conditions expected during testing.

5.1 System Interfaces with Different Cleanliness Levels

When fluid systems are designed or modified, cleanliness breaks shall be established to enable connection of systems that have different cleanliness levels.

a. Use a filter with an appropriate absolute rating for any cleanliness level breaks that have different particulate levels and the same NVR level (e.g., 300A and 400A) or no NVR level (e.g., 300 and 400).

b. Use dual check valves for any cleanliness level breaks that have different NVR requirements (e.g., upstream, 300A; downstream, 300E). Add filter if downstream particulate requirements are more stringent than upstream requirements (e.g., upstream 400A; downstream 100E). An upstream system must have the same or higher NVR cleanliness level requirement than the downstream system (e.g., upstream, 200A;

downstream, 200E or 300B).

5.2 Component Removal

a. Designs for systems and system components should enable the removal of all valves and components from the system.

b. In cases where it is not practical to use removable components (e.g., V-J valves with butt-weld end connections), component design shall enable removal of all internal piece parts of the component while it is connected to its respective system.

c. All removed components shall be replaced with temporary hardware closures and shall meet the requirements in Section 6.4.5.

5.3 Bottles and Vessels

a. Designs of bottles and vessels shall incorporate adequate provisions for cleaning.

b. These provisions shall include, but are not limited to, man-way or "jet-mole" access (to inspect and flush/spray all significant surfaces wetted by service media) and low-point drains (to collect flush samples).

5.4 Materials

Selection of materials used in processing and testing must be compatible with the fluid medium and with the system items.

6. CLEANING

6.1 General

a. Cleaning comprises two categories: rough and precision. Adequate contamination control is imperative to minimize hazards and component failures that result from contamination.

b. Contaminants shall be removed from hardware surfaces in accordance with applicable engineering documents or NASA-approved procedures.

c. Cleanliness is a perishable condition. Careful planning is necessary to achieve and maintain clean surfaces. Such planning includes corrosion protection, surface treatments, material degradation, packaging, handling, processing, controlled environment, etc. If there is concern regarding the effectiveness of the process or possible adverse effects, trial runs using test specimens may be desirable.

6.2 Decontamination

a. All systems, subsystems, components, and items that have been exposed to toxic propellants or hazardous materials (e.g., hypergols) shall be decontaminated to the required level of safe handling before initial cleaning operations.

b. Under no circumstances shall propellant-contaminated systems, subsystems, or components be cleaned or transported directly to a cleaning, calibration, or lab facility before decontamination.

c. Decontamination shall be accomplished using established and proven methods, either in place for removal or neutralization of propellant residues, or hazardous materials or in an area specifically devoted to decontamination operations.

d. No items shall be accepted for cleaning or testing without “proof of decontamination.”

6.3 Cleaning Process Requirements

a. The performing organization is responsible for complying with the requirements of this STD.

The cleaning and cleanliness verification (test) methods must not be detrimental to the materials and/or to the operational requirements of the item or system.

b. The performing organization shall prepare controlled (documented) procedures containing the following information:

1. Description of items to clean, including identification of materials and process precautions to be observed.

2. Cleaning methods used: Alkaline cleaning, acid cleaning, pickling, aqueous or semi aqueous cleaning (with or without ultrasonics or agitation, spray), vapor degreasing, mechanical cleaning (e.g., wire brushing) solvent washing, etc.

3. Orientation of hardware to allow cleaning agents to contact and drain from all critical surfaces.

4. Processing materials/chemicals to be used, including (as applicable) trade names, specifications, chemical and physical properties, and process parameters.

5. The cleaning fluids shall be controlled during use by analysis, solution replacement, or adjustment to maintain cleaning effectiveness and compatibility with the type of material being cleaned.

6. The performing organization shall maintain fluid control records.

7. Records shall indicate scheduled analysis results and any solution replacement or adjustments.

8. Inspection and test methods

9. Drying and preservation methods

10. Controlled areas/product protection and packaging methods

6.4 Hardware Processing

6.4.1 Assembled Items

a. Assembled parts/items that may be damaged during the cleaning operation or that may entrap fluids (because of complexity) shall be cleaned before the joining operation or shall be disassembled to a level to permit cleaning.

b. Subsequent handling and assembly operations shall…