Section 5 — Piping

Piping for Atmospheric and

IPE Engineering Practice IPE-EP-5-6-1

Document number: IPE-EP-5-6-1 · Section: 5 — Piping

SCOPE

This Practice covers mandatory requirements governing the design of piping for storage tanks and storage vessels.
Requirements for Firewater Systems and Foam Systems are covered in EP 3–5–2 and EP 3–5–4, respectively.
Any deviation from this Practice must be approved by the procedure described in EP 1–1–3.
An asterisk (*) indicates that a decision by the Owner’s Engineer or Owner is required, or that additional information is furnished by the Purchaser.

2.0 REFERENCES

The latest edition of the following standards and publications are referred to herein.

STANDARDS AND PUBLICATIONS

IPE Engineering Practices	IPE Engineering Practices
EP 1–1–3	Deviations to IPE Engineering Practices
EP 3–5–2	Firewater Systems
EP 3–5–4	Foam Fire Protection Systems
EP 3–7–1	Pressure Relieving Systems
EP 5–1–2	Piping Layout
EP 5–1–3	Piping Stress Analysis and Supports
EP 5–2–1	Selection of Piping Components and Materials
EP 5–5–1	Piping Fabrication
EP 5–5–2	Welding Requirements for Piping
EP 5–5–3	Piping Erection and Testing

DEFINITIONS

Owner - Inflection Point Engineering, LLC.
Owner’s Engineer - A Inflection Point Engineering, LLC appointed engineer.

PIPING LAYOUT, DESIGN AND FABRICATION

General layout and arrangement requirements for all piping associated with tankage (process, fuel systems and utility) are stipulated in EP 5–1–2. Supplemental layout and arrangement requirements for these systems are specified in this Practice.
Design of piping systems for tankage shall be in accordance with EP 5–1–3.
General selection of pipe and piping components for tankage piping systems shall be in accordance with EP 5–2–1.
Fabrication, erection and testing of tankage piping systems shall be in accordance with EP 5–5–1, EP 5–5–2, and EP 5–5–3.

PIPING AUXILIARIES AND CONNECTIONS

Vessel filling and discharge piping shall be installed with a minimum number of flanged connections and fittings.
All tank nozzles, except those for atmospheric vents on fixed roof storage tanks, shall be valved, using gate valves located at the tank nozzles.
Requirements for liquid thermal relief protection of piping systems associated with tankage shall be in accordance with EP 3–7–1.
Additional requirements for refrigerated storage vessels are as follows:
The block valve adjacent to the vessel in the main process piping (fill and discharge lines) shall be motor operated. The valve motor operator and leads shall be fireproofed. An emergency OPEN–CLOSE pushbutton control shall be located outside the dike.
All connections below the liquid level shall be provided with a block valve, installed as follows:
For single wall vessels, the block valve shall be located adjacent to the shell insulation.
For double wall vessels, the block valve shall be located adjacent to the outer shell. There shall be no flanged joints between the connection to the inner wall and the flange at the block valve.
Piping connections between the tank and the block valve are prohibited.
Liquid drawoff piping leading to the atmosphere or to an open container shall be double valved.
Additional requirements for pressurized (excluding refrigerated) storage vessels are as follows:
Liquid drawoff piping leading to the atmosphere, or to an open container, shall be double valved if the vessel contains stocks which can auto–refrigerate. The valve next to the shell shall be a quick action type, such as a metal–seated plug valve. The second valve, for flow control, shall be of a type suitable for partially open operation.
Water drawoff piping shall discharge at a point not less than 15 feet from the peripheral boundary of the storage vessel. The discharge shall be so located that any flammable spillage will drain away form the vessel.
The block valve adjacent to the storage vessel in the main process piping—fill lines if located below the liquid level, and discharge lines—shall be motor operated and remotely controlled from outside the dike. The valve actuator and leads shall be fireproofed.

ADDITIONAL REQUIREMENTS FOR SPECIAL STORAGE PRODUCTS

Additional requirements for asphalt and “hot” oil (above 250 F) storage vessels are as follows:
Separate fill and discharge systems, without interconnections between the fill and discharge piping or to other systems, shall be provided to reduce the risk of injection of water or light ends, Reid Vapor Pressure of 15 psia or greater.
Only external steam tracing shall be used on fill and discharge lines.
(*)Liquids classified as static electrical accumulators shall be specified by the Owner’s Engineer. Additional requirements for stored products classified as static electrical charge accumulators are as follows:
Overhead fill lines are prohibited.

(*)Jet mixing nozzles or mechanical agitators are not permitted in fixed cone roof tanks where products stored are static accumulators, if the vapor space may be in the flammable range.
(*)Where products stored are static accumulators, a valved bypass to an API Low Type or Regular Type nozzle shall be provided around elevated inlet nozzles or jet mixing nozzles to permit initial filling without splashing or spraying.
(*)Where products stored are static accumulators classified as either intermediate vapor pressure stocks or low vapor pressure stocks which are handled at a temperature within 15 F of, or higher than, their flashpoint, inlet nozzles to tanks and vessels (excluding floating roof tanks) shall be sized to meet the criteria shown in Table 1.
Where filters are installed on tank inlet piping, the pipe design shall provided at least 30 seconds of residence time between the filters and the tank to allow for electrostatic charge “relaxation.” This may be accomplished by enlarging or lengthening the affected portion of the inlet piping.

7.0 TABLES

TABLE 1

SIZING REQUIREMENTS FOR INLET NOZZLE

Tank Capacity (gallons)	Inlet Velocity, Max (ft/sec)
1 0,000 >10,000	20 35

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