Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
API RP 1107-1991: Recommended Practice for Pipeline Pigging Operations — A Technical Overview
Scope, Technical Requirements, Implementation, and Compliance Guidelines for Safe and Efficient Pipeline Pigging
API RP 1107-1991, ‘Recommended Practice for Pipeline Pigging Operations,’ sets forth industry-accepted guidelines for the design, selection, operation, and maintenance of pipeline pigging systems. Developed by the American Petroleum Institute (API), this recommended practice (RP) is applicable to both onshore and offshore pipelines transporting oil, natural gas, and petrochemical products. Although the document was published in 1991, its principles continue to form the backbone of modern pigging operations.
Scope
The scope of API RP 1107-1991 encompasses all activities related to pipeline pigging, including:
- Selection and specification of pig types (cleaning, inspection, and sealing/utility pigs).
- Design and installation of pig launchers and receivers.
- Launching and receiving procedures.
- Safety analysis and hazard mitigation.
- Pig tracking and data collection.
- Maintenance and troubleshooting of pigging equipment.
The standard is intended for use by pipeline operators, design engineers, and field personnel. It does not cover pipeline design or structural integrity except where directly affected by pigging loads.
Technical Requirements
This section details the technical criteria that must be met to ensure safe and effective pigging.
Pig Classification and Selection
Pigs are selected based on the purpose of the run. Table 1 outlines common pig types and their applications.
| Pig Type | Primary Application | Key Characteristics |
|---|---|---|
| Foam Pig | Light cleaning, drying, product removal | Flexible, low-cost, available in various densities |
| Solid Cast Pig | Medium-to-heavy cleaning | Durable, often equipped with cups or blades |
| Magnetic Cleaning Pig | Ferrous debris removal | Incorporates magnets to capture metal fragments |
| Smart Pig (Inspection) | In-line inspection (ILI) | Carries sensors (MFL, ultrasonic, caliper) |
| Gel Pig | Specialized cleaning or batching | Uses viscous gel, often combined with other pigs |
Launcher and Receiver Design
The standard mandates that launchers and receivers be designed with safety as a priority. Key requirements include:
- Barrel length must accommodate the longest pig plus sufficient clearance.
- Closure must be quick-acting and equipped with a safety interlock to prevent opening under pressure.
- Pressure rating to match or exceed the pipeline MAOP.
- Bleed-off valve and vent line sized for safe depressurization.
- Kick-out line and check valve arrangement to prevent backflow.
Warning: Closures must be interlocked to prevent opening when pressure is present. Multiple incidents have occurred due to bypassed or inoperative interlocks.
Operating Conditions
Parameters such as flow velocity, pressure differential, and temperature must be considered to ensure efficient pig travel. The standard provides guidance on minimum and maximum velocities for different pig types and pipeline conditions.
Implementation Highlights
Successful implementation of API RP 1107-1991 requires a systematic approach.
Pigging Program Development
Operators should develop a pigging program based on pipeline characteristics, product type, and integrity goals. The program should define:
- Frequency of pigging runs.
- Criteria for pig selection.
- Pre‑ and post‑pigging procedures.
- Contingency plans for stuck pigs.
Training and Safety
All personnel involved must be trained in the specific procedures and hazards of pigging. The standard calls for periodic drills and refresher training.
Tip: Use a pig simulation tool to predict pig behavior in complex pipelines. This can reduce the risk of stuck pigs and optimize operational parameters.
Data Management
Inspection data from smart pig runs must be analyzed and stored for trend analysis. The standard recommends establishing a database that tracks pig runs and anomalies.
Compliance Notes
API RP 1107-1991 is a recommended practice, not a mandatory standard. However, it is widely referenced by regulatory bodies and industry contracts.
Regulatory Adoption
- The U.S. Department of Transportation (DOT) and Pipeline and Hazardous Materials Safety Administration (PHMSA) often cite API RP 1107 in safety regulations.
- Many international operators adopt it as a basis for their pigging procedures.
Relationship with Other Standards
Pigging systems involve components that may fall under other standards (e.g., API 6D for valves, ASME B31.4/B31.8 for pipelines). Compliance with API RP 1107 should be considered alongside these standards to ensure a coherent design.
Note: While the 1991 edition may suffice for legacy systems, new installations should refer to the latest edition and any applicable jurisdictional requirements.
Audit and Verification
Operators following API RP 1107 are better prepared for regulatory audits. Documented procedures, training records, and pig run reports demonstrate compliance.
Benefits
- Enhanced pipeline integrity and reduced failure risk.
- Improved operational efficiency and reduced downtime.
- Clear procedures for safe pig handling.
Q: What are the main updates in later editions of API RP 1107?
A: Later editions include expanded guidance on smart pigging, risk assessment, and compatibility with other integrity management practices. Always use the most recent version for new projects.
A: Later editions include expanded guidance on smart pigging, risk assessment, and compatibility with other integrity management practices. Always use the most recent version for new projects.
Q: Can API RP 1107 be used for unpiggable pipelines?
A: The standard focuses on piggable systems. For unpiggable pipelines, alternative assessment methods are needed, though some of the safety principles still apply.
A: The standard focuses on piggable systems. For unpiggable pipelines, alternative assessment methods are needed, though some of the safety principles still apply.
Q: Is there a specific training requirement in API RP 1107?
A: The standard recommends that personnel be adequately trained and that operator qualifications be documented, but it does not prescribe specific training programs or certifications.
A: The standard recommends that personnel be adequately trained and that operator qualifications be documented, but it does not prescribe specific training programs or certifications.
Q: What is the difference between a launcher and a receiver?
A: A launcher is used to insert a pig into the pipeline, while a receiver is used to extract it. Both consist of a barrel and closure, but their auxiliary piping and valves differ to suit different functions.
A: A launcher is used to insert a pig into the pipeline, while a receiver is used to extract it. Both consist of a barrel and closure, but their auxiliary piping and valves differ to suit different functions.
This article is provided for informational purposes and does not constitute legal or professional advice. Always consult the latest edition of API RP 1107 and applicable regulations. — Published 2026.