API 570 covers inspection, rating, repair, and alteration procedures for metallic and fiberglass reinforced plastic (FRP) piping systems and their associated pressure relieving devices that have been placed inservice.
The intent of this code is to specify the in-service inspection and condition-monitoring program that is needed to determine the integrity of piping. That program should provide reasonably accurate and timely assessments to determine if any changes in the condition of piping could possibly compromise continued safe operation. It is also the intent of this code that owner-users shall respond to any inspection results that require corrective actions to assure the continued safe operation of piping.
API 570 was developed for the petroleum refining and chemical process industries but may be used, where practical, for any piping system. It is intended for use by organizations that maintain or have access to an authorized inspection agency, a repair organization, and technically qualified piping engineers, inspectors, and examiners, all as defined in Section 3.
API 570 shall not be used as a substitute for the original construction requirements governing a piping system before it is placed inservice; nor shall it be used in conflict with any prevailing regulatory requirements. If the requirements of this code are more stringent than the regulatory requirements, then the requirements of this code shall govern.
The term non metallics has a broad definition but in this code refers to the fiber reinforced plastic groups encompassed by the generic acronyms FRP (fiberglass-reinforced plastic) and GRP (glass-reinforced plastic). The extruded, generally homogenous nonmetallics, such as high and low-density polyethylene are excluded. Refer to API 574 for guidance on degradation and inspection issues associated with FRP piping.
Included Fluid Services
Except as provided in 1.2.2, API 570 applies to piping systems for process fluids, hydrocarbons, and similar flammable or toxic fluid services, such as the following:
a) raw, intermediate, and finished petroleum products;
b) raw, intermediate, and finished chemical products;
c) catalyst lines;
d) hydrogen, natural gas, fuel gas, and flare systems;
e) sour water and hazardous waste streams above threshold limits, as defined by jurisdictional regulations;
f) hazardous chemicals above threshold limits, as defined by jurisdictional regulations;
g) cryogenic fluids such as: LN2, LH2, LOX, and liquid air;
h) high-pressure gases greater than 150 psig such as: GHe, GH2, GOX, GN2, and HPA.
Optional Piping Systems and Fluid Services
The fluid services and classes of piping systems listed below are optional with regard to the requirements of API 570.
a) Fluid services that are optional include the following:
1) hazardous fluid services below threshold limits, as defined by jurisdictional regulations;
2) water (including fire protection systems), steam, steam-condensate, boiler feed water, and Category D fluid services, as defined in ASME B31.3.
b) Other classes of piping systems that are optional are those that are exempted from the applicable process piping construction code.
Fitness-For-Service and Risk-Based Inspection (RBI)
This inspection code recognizes Fitness-For-Service concepts for evaluating in-service damage of pressure-containing components. API 579 provides detailed assessment procedures for specific types of damage that are referenced in this code. This inspection code recognizes RBI concepts for determining inspection intervals. API 580 provides guidelines for conducting a risk-based assessment.