Selection of Cleaning Agents & Methods for Equipment for Oxygen Service

This article is about Selection of Cleaning Agents and Methods for Equipment Used in Oxygen Service related to topic of Cleaning System in Plants and Petrochemical Plants as per International Codes & Standards. Here furthermore will be discussed about Clean for Oxygen Service Standards, Cleaning Procedure for Oxygen Service, ASTM G93 Pdf, Chemical Cleaning Oxygen Pipelines, Oxygen Cleaning Products in Plant and Petrochemical Plants.

1. Purpose – This procedure defines acceptable cleaning agents and cleaning methods for equipment in oxygen service and to ensure that all methods and cleaning agents used for oxygen cleaning are approved for use.

2. Scope – This procedure applies to all engineering, operations, and construction activities associated with oxygen cleaning of equipment manufactured.

3. Definitions

4. Selection of Cleaning Agents and Methods for Equipment Used in Oxygen Service

4.1 The objective is the minimization of all the safety, health and environmental risks associated with cleaning equipment for oxygen service.

4.2 Prior to be being placed into oxygen service for the first time oxygen containing systems or equipment with oxygen shall have been cleaned and inspected to meet the acceptance criteria.

4.3 Only methods and solvents approved by means of this procedure shall be used for cleaning of oxygen systems. Whenever practical, aqueous (water based) cleaning agents should be utilized as they offer environmental, health and safety advantages.

4.4 Company facilities and operations that are involved with cleaning for oxygen service shall not use 1,1,1-trichloroethane (TCA) or any other significant ozone-depleting chemical as a degreasing or cleaning agent. Likewise trichloroethylene, a known carcinogen, shall not be used.

4.5 Written procedures that have been developed through workplace risk assessment and job safety analysis shall be used for oxygen cleaning. Only persons who have been specifically trained for cleaning equipment and systems for oxygen service shall carry out cleaning or inspection of systems for oxygen cleanliness.

4.6 Only approved suppliers shall be used for supply of services or equipment involving oxygen cleaning.

4.7 When feasible, all parts and equipment shall be cleaned for oxygen service by the manufacturer or supplier prior to installation. Procedures that will ensure the maintenance of cleanliness until final assembly must be implemented.

4.8 Prior to be being placed into oxygen service following maintenance, all equipment and pressure systems in contact with oxygen shall have been cleaned and inspected to meet the acceptance criteria (see Following Engineering Articles Section).

4.9 Equipment and systems that have been cleaned for oxygen service shall be sealed by suitable means and identified as Cleaned for Oxygen Service and a certificate provided.

5. PROCEDURE

5.1 Approved Methods for Oxygen Cleaning

Approved methods for cleaning for oxygen service are given in this article Cleaning Procedures for Oxygen Service Based on Application. Guidance is also given in reference documents from ASTM, CGA, and EIGA. Appropriate written procedures must be developed for each cleaning method and/or agent to ensure safety, health, and environmental aspects as well as the required cleaning level.

Procedures and periodic training are being relied upon to achieve the cleanliness. Managers are responsible for establishing training, certification programs, and developing safe and environmentally sound work practices in accordance with Risk Assessment and JSA procedures. Check Approved cleaning Agents.

5.1.1 The use of Low Vapor Pressure (LVP), slow-evaporating, hydrocarbon-based cleaning agents (for example, terpenes) shall be strongly discouraged because of the risk of a hydrocarbon residue remaining in the system and subsequently contacting oxygen. LVP solvents require special training and procedures to mitigate this risk. In addition, LVP cleaning agents are usually flammable and/or combustible.

5.1.2 The use of High Vapor Pressure (HVP), fast-evaporating, hydrocarbon-based cleaning agents, which are also flammable, shall be minimized. They shall be used only for applications when other cleaning agents or methods are not practical. The use of flammable HVP cleaning agents always requires extreme care, special training, and written procedures. Flammable HVP cleaning agents shall not be sprayed.

5.2 Isopropyl Alcohol

5.2.1 Isopropyl alcohol (also known as IPA and isopropanol) is between a LVP and a HVP solvent.  With certain exceptions IPA has not been approved (Appendix B) because it is a poor solvent  to remove organics, is flammable, has a high boiling point and has a high heat of vaporization. The latter two properties greatly impede its evaporation. IPA is often contaminated with water, which further impedes its evaporation. IPA is ineffective for soaking to remove organics.

5.2.1.1 The non approval of IPA as a solvent has some limited exceptions. IPA is approved for:

• Spot light duty cleaning with Rocol spray.

• Spot light duty cleaning (fingerprints, lint, etc.) by wiping with a clean rag dipped in IPA.

5.2.1.2 In the following circumstances IPA may be used following a risk assessment and JSA approved by the appropriate EHS representative.

• At sites where the property owner has a written policy prohibiting the use of chlorinated solvents but approving the use of IPA.

• In such cases AP policy and procedures shall be explained in writing to the property owner.

5.2.1.3 The above exceptions do not include soak cleaning with IPA.

5.2.1.4 When used, ample time and/or purge flow is required for complete evaporation of the IPA.

5.2.1.5 Isopropyl alcohol is approved for use as a lubricant for assembling blocks of packing in ASU columns. This approval is based upon the fact that small amounts are used and that very ample time is available for the IPA to evaporate before the oxygen would be placed in the column.

5.3 Methylene Chloride in Open and Closed Systems

5.3.1 Methylene chloride (also known as dichloromethane) is an inexpensive and excellent HVP solvent. Further, it has a very low ozone depleting potential. To prevent potential adverse health effects, a full JSA/risk assessment must be conducted for each activity requiring the use of methylene chloride to establish the necessary control and handling measures.

5.3.2 US Only – Methylene chloride is regulated as a potential carcinogen by the Occupational Safety and Health Administration (OSHA), therefore its use is discouraged in the United States. If methylene chloride must be used for a particular application, contact Company Industrial Hygiene for compliance guidance.

5.3.4 For health reasons as well as for soil and water environmental concerns, methylene chloride shall be used in closed (recovery) systems. Escaping vapors must be vented to a safe location away from personnel and comply with relevant environmental legislation.

5.3.5 Methylene chloride may only be used in open systems if the specific application is approved by the OSC, Industrial Hygiene (US/Asia), and/ or the Field Safety Group (Europe).

5.3.3 Methylene chloride may be used as a cleaning agent for complex plant washouts in accordance with Gases Operations Procedure 34-110919. Contact Department of Industrial Hygiene or the Field Safety Group (Europe) for guidance.

5.6 Approval Process for New Solvents

5.6.1 The approval process for a new solvent is summarized in following process diagram.

5.6.2 The initial inquiry should be made through EH&S Process Safety Group (US) or the European EH&S Group. Initial information should include:

• Application and method.
• Is it a new technique/product for an existing application?
• Does it have advantages over existing technique/product?
• Costing.
• Availability.
• Available vendor technical data.

5.6.3 The item will be presented for discussion at the appropriate Approval Committee with a request for a decision to be made on the Solvent Approval. It is envisaged that this type of presentation would be on an ‘as needed’ basis. Feedback would be directed back to those persons who made the initial inquiries as well as to the relevant experts, including liaison with the Oxidizer Safety Committee (OSC).

5.6.4 Proper alternative cleaning methods or agents shall be selected based on contamination being removed, material being cleaned, and local conditions. Local conditions include the following:

• Environmental regulations (all levels of government).
• Availability of utilities (for example, electrical power, hot water).
• Ambient temperatures and availability of a heated enclosure to aid drying.
• Availability of cleaning agents.
• Shipping of cleaning agents.
• Competence/Training of individuals.
• Safe and environmentally sound disposal of spent cleaning agents and wipers.

5.6.5 If a new solvent for oxygen cleaning is approved as a result of a decision from the Approval Committee then the listing from Appendix A will be updated.
5.6.6 The new method or solvent shall be subject to a risk assessment/job safety analysis and written procedures and training developed prior to final approval and implementation.

5.7 Oxygen Cleaning by Suppliers and Contractors

5.7.1 Suppliers of equipment that requires cleaning for oxygen service shall be informed of the methods and agents defined by this standard to understand the minimum requirements for cleaning.
5.7.2 The responsibility for attaining the levels of cleanliness specified in the oxygen acceptance criteria rests with the supplier.

5.7.3 All contractors performing oxygen cleaning shall, under the supervision of Company or Contractor.

5.8 Acceptance Criteria

Acceptance criteria are given in 3PI70001 Cleaning Levels and Acceptance Criteria for Air Separation Plant Piping and Equipment or AO3 Oxygen Clean (Class AA) Inspection and Acceptance Requirements.

5.9 Waste Disposal

Spent cleaning agents and any associated cleaning materials (for example, cloths and wipers) might need to be categorized as hazardous wastes and disposed of properly. The appropriate national or regional environmental coordinator shall be consulted for proper disposal guidance.  For guidance on the correct disposal of cleaning agents refer to 25-011202, Waste Management.

5.10 Health Assessment

When using cleaning agents, handling precautions specified by the supplier and Material  Safety Data Sheet (MSDS) shall be used as part of the risk assessment to determine the correct controls (in Europe refer to 25-011313AN). The risk assessment shall be used to define the requirements for health surveillance (see Health Screening and Surveillance procedure).

6. RELATED ARTICLES

6.1 EH&S Documents

25-010501 Job Safety Analysis (JSA)/Workplace Risk Assessment
25-011202 Waste Management
25 011206  Ozone Depleting Substances
25-011209AM Environmental Risk Assessment
25-011212AN  Environmental Aspects and Risk Assessment
25-011313AN  Chemical Agents Risk Assessment
25-011314AM Hazard Communication

6.2 Operations Documents

34-110919 Plant Washout (cleaning agent or solvent)

6.3 Engineering Articles

3PI70001 Cleaning Levels and Acceptance Criteria for Air Separation Plant Piping and Equipment

4WPI-SW70003 Oxygen Clean (Class AA) Inspection and Acceptance Requirements.

6.4 European Industrial Gases Association (EIGA)

EIGA Document 33   Cleaning Equipment for Oxygen Service

6.5 American Society for Testing and Materials (ASTM)

ASTM G93-96 Standard Practice for Cleaning Methods and Cleanliness Levels for Material and Equipment Used in Oxygen Enriched Environments

6.6 Compressed Gas Association, Inc. (CGA)

CGA Pamphlet G-4.1 Cleaning Equipment for Oxygen Service

Cleaning Procedures for Oxygen Service Based on Application

Oxygen Cleaning Solvent Selection Process