Section 5 — Piping

IPE Piping Standards

IPE Engineering Practice IPE-EP-5-2-2

Document number: IPE-EP-5-2-2 · Section: 5 — Piping

SCOPE

This Practice covers requirements governing the selection of flanges, gaskets, and bolting for piping systems. In addition, this Practice also covers supplemental requirements for flanges, gaskets, and bolting for pressure vessels, heat exchangers and tankage. The requirements in this Practice form the basis of the flange, gasket and bolting requirements contained in

EP 5–2–3.

When modifications to flanges, gaskets, and bolting on existing equipment are made, they shall meet the requirement of this Practice and shall be made in accordance with EP 7–3–3.
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 to be furnished by the Purchaser.
A revision bar indicates all changes made to this Revision.

2.0 REFERENCES

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

STANDARDS AND PUBLICATIONS

IPE Engineering Practices
EP 1–1–3 Deviations to IPE Engineering Practices EP 5–1–1 General Piping Design EP 5–2–1 Selection of Piping Components and Materials EP 5–2–3 IPE Piping Standards EP 5–10–1 Supplemental Requirements for Piping in HF– Service (Phillips) EP 5–10–2 Supplemental Requirements for Piping in HF– Service (UOP) EP 7–1–1 Pressure Vessels EP 7–3–3 Repairs and Alterations to Flanges EP 10–2–1 Material Requirements for Aggressive Environmental Services EP 11–3–6 Insulation of Flanged Joints and Valves in Hot Service
API Publications
Publ 941 Steels for Hydrogen Service at Elevated Temperatures and Pressures in Petroleum Refineries and Petrochemical Plants
ASME Codes
Sec ll Material Specifications Sec VIII Pressure Vessel Code, Division 1 B31.3 Process Piping

STANDARDS AND PUBLICATIONS (CONTINUED)

ASTM Standards	ASTM Standards
A193	Alloy–Steel and Stainless Steel Bolting Materials for High–Temperature Services
A194	Carbon and Alloy Steel Nuts for Bolts for High–Pressure and High–Temperature
	Service
A 234	Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for
	Moderate and Elevated Temperatures
A307	Carbon Steel Externally and Internally Threaded Standard Fasteners
A320	Alloy Steel Bolting Materials for Low–Temperature Service
A403	Specification for Wrought Austenitic Stainless Steel Piping Fittings
A453	Specification for Bolting Materials, High–Temperature, 50 to 120 ksi yield
	strength, with Expansion Coefficients Comparable to Austenitic Steels.
F468	Specification for Nonferrous Bolts, Hex Cap Screws, and Studs for General Use
ASME/ANSI Standards	ASME/ANSI Standards
B1.20.1	Pipe Threads, General Purpose (Inch)
B16.1	Cast Iron Pipe Flanges and Flanged Fittings, Classes 25,125, 250, and 800 LB.
B16.5	Steel Pipe Flanges, Flanged Valves, and Fittings
B16.20	Metallic Gaskets for Pipe Flanges - Ring–Joint, Spiral–Wound, and Jacketed
B16.21	Nonmetallic Gaskets for Pipe Flanges
B16.25	Buttwelding Ends
B16.36	Orifice Flanges
B16.42	Ductile Iron Pipe Flanges and Flanged Fittings
B16.47	Large Diameter Steel Flanges
ANSI Standard	ANSI Standard
B16.11	Forged Steel Fittings - Welding and Threaded
MSS Publication	MSS Publication
SP-44	Steel Pipe Line Flanges

DEFINITIONS

Aggressive Environmental Service (AES) - Process services which result in material degradation such as cracking, scaling, blistering, and severe pitting and/or corrosion. Examples of such services are hydrogen service, wet hydrogen sulfide, cyanides, caustic, amine, and hydrofluoric acid. AES process fluid are defined in EP 10–2–1.
Category D Fluid Service - A fluid service, as defined in accordance with ASME B31.3, in which all of the following apply.
The fluid handled is non–flammable, non–toxic, and not damaging to human tissues as defined in paragraph 300.2 of ASME B31.3.
The design gauge pressure does not exceed 150 psi.
The design temperature is from -20 F through 366 F.

Hydrogen Rich Service - A service defined as a combination of hydrogen partial pressure and temperature at or below the curve for carbon steel per Figure 1 of API Publication 941, latest edition, and with a hydrogen partial pressure greater than 100 psia.
Hydrogen Service - A service defined as a combination of hydrogen partial pressure and temperature above the curve for carbon steel per Figure 1 of API Publication 941, latest edition.
Inspector - A Inflection Point Engineering, LLC appointed engineer or inspector.
Manufacturer - The recipient of a direct or indirect purchase order for materials and/or equipment. In this context, a direct order is one issued to a manufacturer by a contractor or the Owner. An indirect order is one issued to a manufacturer by a vendor (recipient of a direct order) for materials, fabricated components, or subassemblies.
Owner - Inflection Point Engineering, LLC.
Owner’s Engineer - A Inflection Point Engineering, LLC appointed engineer.
Purchaser - The party placing a direct purchase order. The purchaser is the Owner’s designated representative.

FLANGES

(*)All flanges shall be in accordance with the applicable Industry Standards shown in Table 1. Permissible flange materials shall be in accordance with EP 5–2–1 and EP 7–1–1, as applicable. The design of flanges not shown in Table 1 are subject to the approval of the Owner’s Engineer.
Design limits, facing and gasket requirements for piping, nozzle and manways flanges shall be in accordance with Table 2. Design limits, facing and gasket requirements for services not covered in Table 1 are subject to the approval of the Owner’s Engineer.
Pressure–temperature ratings for flanged joints shall be per the applicable flange standard, see Table 1.
(*)The temperature reduction permitted by the ASME B31.3 Piping Code and EP 5–1–1 for uninsulated flanges shall not be used unless approved by the Owner’s Engineer.
ASME/ANSI B16.5 class 400 flanges shall not be used.
(*)Flange facing finish shall be per the applicable flange standard, see Table 1. Unless otherwise specified by the Owner’s Engineer, the gasket contact surface for flanges to be used with spiral wound gaskets shall have a finish within the range of 125  inch to 250  inch arithmetic average (Ra).
(*)Proprietary piping components such as PLIDCO flanges, WELD–PLUS–ENDS, and GARLOCK or REFLANGE connectors shall not be used without approval of Owner’s Engineer. When the use of such devices is approved, they shall be designed in accordance with the ASME Code, Section VIII, and shall be applied in accordance with the manufacturer’s recommendations and additional instructions (if any) from the Owner’s Engineer.
The use of slip–on flanges is subject to the following limitations:
They shall be used only as piping flanges; weld neck flanges or long weld necks shall be used for all pressure vessels and heat exchangers per EP 7–1–1.

They shall not be used above 750F, or for ASME/ANSI B16.5 Class 600 and higher pressure ratings.
They shall not be used in Erosive Service or Corrosive Service where the specified corrosion allowance exceeds 1/8 inches.
They shall not be used in Cyclic Service.
They shall not be used in Lethal service as defined by the ASME Code.
In Hydrogen Service or Hydrogen Rich Service, flanges shall be furnished predrilled with a 1/8– inch diameter hole to vent diffused hydrogen from the space between the OD of the pipe and the bore of the flange.
They shall not be welded directly to welding fittings.
The use of lap joint flanges is subject to the following limitations:
They shall be used only as piping flanges.
They shall not be used above 750F, or for ASME/ANSI B16.5 Class 600 or higher pressure ratings.
They shall not be used where the combined longitudinal stress in the pipe where attached to the lap–joint stub–end, resulting from pressure, weight, and thermal expansion, exceeds the ASME B31.3 allowable stress at the pipe design temperature.
Lap joint stub ends shall conform with ASME B16.9 dimensions and ASME B 31.3. Class WP ASTM wrought fittings are required. The stub end thickness shall be in accordance with the requirements of Table 3.
Lap joint backing flanges shall be forged carbon steel. Slip–on flanges shall not be permitted for use as backing flanges in lap joints.
Lap joint stub ends shall have a flatness tolerance of ”0.0035 inches over the entire circumference. Front and back faces shall be parallel.
The flange may be of material different from that of the pipe provided galvanic corrosion will not occur (e.g., carbon steel flanges may be used on lap–joint–stub–ended stainless steel pipe in above–ground service).
Lap joint flanges shall not be used with ring joint gaskets.
(*)Suitability of flanged joints for services under bending loads must be confirmed by calculations when the pipe diameter exceeds NPS 12 and the pipe design temperature exceeds 650 F, and for all temperatures when the diameter exceeds NPS 24. The calculation procedures used for this analysis are subject to the approval of the Owner’s Engineer.
(*)Electrically insulated flanged joints (joints which will not conduct electricity across the flange connection) shall not be used without approval of Owner’s Engineer. If approved for use, electrically insulated flange joints shall comply with the following:
Electrically insulated joints shall be used to isolate lines heated by electric impedance heating systems.
These joints shall be considered for:
Cathodically protected systems.

Stray current protection for pipelines used to load or unload barges, tankers, tank cars, or tank trucks when the fluids have closed cup flash points less than 130F or which are at a temperature above or within 15 F of their flash points.
The joint assembly shall be designed to use a central insulating gasket, insulating bolt sleeves and washers, and steel bolt back–up washers. The central gasket shall be made from a material with nonconductive binders and impregnates. Gaskets shall be suitable for the service fluid, pressure, and temperature.
(*)Threaded steel flanges shall not be used without approval of the Owner’s Engineer.
Cast iron flanges are permitted only if furnished as integral flanges on cast iron piping or equipment.
(*)Aluminum alloy flanges shall not be used without approval of the Owner’s Engineer. If approved, they shall be either wrought or forged.
If flanges are to be insulated, they shall comply with the requirements of EP 11–3–6.
Unless otherwise specified by the Purchaser, flanges shall be furnished to match the size, bore, thickness and pressure rating of the attached pipe. End preparation of flanges shall conform to the following Standards:
Weldneck flanges: ASME/ANSI B16.25, Figure 2A or 3A as applicable
Socketweld flanges: ANSI B16.11
Threaded flanges: ASME/ANSI B1.20.1

GASKETS

The selection of gasket type for piping systems shall be based on the requirements given in Table 2. Gasket selection for service conditions not covered in Table 2 are subject to the approval of the Owner’s Engineer.
(*)The selection of gasket type for pressure vessels and the exchangers shall be approved by the Owner’s Engineer.
Requirements for spiral wound gaskets are covered in Table 4 and shall be color–coded per ASME/ANSI B16.20.
Ring joint gaskets shall be in accordance with ASME/ANSI B16.20 and shall meet the following requirements.
Permissible ring joint materials are shown in Table 5.
Soft iron or low carbon content steel oval ring gaskets are satisfactory for carbon steel piping with a maximum corrosion allowance of 0.050 inches. Oval ring gaskets of a material other than soft iron or low carbon content steel shall be used if the corrosion allowance is greater than

0.050 inches. The ring material selected shall have a corrosion rate of less than 0.010 inches/year.

(*)The hardness of the ring gasket shall be lower than that of the flange. Where it is not possible to obtain this hardness differential, the material selection shall be approved by the Owner’s Engineer.
Sheet gaskets shall be in accordance with the following requirements.

(*)Service limitations for sheet gaskets are given in Table 2 and Table 6. Sheet gaskets can be used in hydrocarbon, steam and boiler feed water if approved by the Owner’s Engineer.
Sheet gaskets shall have a flat ring shape with dimensions in accordance with ASME/ANSI B16.21.
Thickness and material requirements for sheet gaskets are covered in Table 6.
Requirements for metal jacketed gaskets are covered in Table 7.
Solid flat metal gaskets shall meet the following requirements.
Solid flat metal gasket material and hardness requirements are covered in Table 8.
Restrictions on the thickness of solid flat metal gaskets are covered in Table 9.

BOLTING

(*)Except where stress corrosion cracking is a consideration, bolting shall be used as specified in Table 10. In environments that cause stress corrosion cracking (SCC) of low–alloy or carbon steel bolting, the bolting shall be as shown in Table 11. The use of bolting not specified in Table 10 and Table 11 requires the approval of the Owner’s Engineer. Note that bolting

materials used for pressure vessel and heat exchanger components shall be in accordance with the ASME Code, Section II.

(*)All bolting, except in water service, shall be of the stud bolt type with continuous full length threads. Bolt lengths shall be calculated and specified in accordance with ASME/ANSI B16.5. When approved by the Owner’s Engineer, cap screws may be used for flange connections when through stud bolt clearance is not available.
Bolting for nonferrous flanges and for nonmetallic flanges having a metal temperature between - 20 F and 800 F shall be ASTM A193 Grade B7 if galvanic corrosion is not an expected problem.
(*)Carbon steel bolting conforming to ASTM A307 Grade B may be considered for Category D fluid service. Use of such bolting requires approval of the Owner’s Engineer.
Bolts with either zinc or cadmium plating shall not be used in hydrocarbon or toxic service, nor in any service above 400 F.
Bolting for marine environments shall be coated with ceramic–filled fluorocarbon (Stand–Cote SC–1).Other manufacturers of coated bolting shall provide evidence that bolts and nuts are equivalent to Stand–Cote SC–1. Evidence shall include a laboratory evaluation (at manufacturer’s expense before delivery, if accepted) of randomly selected bolts.
(*)Coatings for flange bolting shall not be specified except when approved by Owner’s Engineer for highly corrosive areas such as cooling towers and docks.
(*)Bolt selection for bimetallic flanges shall be approved by Owner’s Engineer.
If austenitic bolting is to be used with ferritic flanges operating above 400 F, the flanges shall not be insulated.
Unless otherwise specified by the Purchaser, stud bolts shall be threaded full length and each bolt shall be supplied with two (2) semi–finished heavy hex nuts. In addition, bolt assemblies over 1–1/2 inch in diameter shall be furnished with hardened washers.

7.0 TABLES

TABLE 1

FLANGE STANDARDS

Flange Material/Type	Size flange (NPS, inches)	Applicable Industry Standards
Steel Nickel Nickel Copper (Monel) Inconel (Alloy 600) Incoloy (Alloys 800, 800H)	1/2 thru 24	ASME/ANSI B16.5
Steel Nickel Nickel Copper (Monel) Inconel (Alloy 600) Incoloy (Alloys 800, 800H)	Over 24	ASME/ANSI B16.47 Series B (1) or ASME Section VIII
Orifice Flanges (For materials listed above)	1 thru 24	ASME/ANSI B16.36
Ductile Iron Flanges	1 thru 24	ASME/ANSI B16.42
Cast Iron Flanges (2)	1 thru 96	ASME/ANSI B16.1

NOTES:

ASME/ANSI B16.47- Series A flanges may be used if required to mate with equipment. Note that ASME/ANSI B16.47–Series A flanges are equivalent to MSS SP–44 flanges, and ASME/ANSI B16.47–Series B flanges are equivalent to API Std 605 flanges.
Use only to mate with equipment.

TABLE 2

DESIGN LIMITS, FLANGE FACING AND GASKET TYPES FOR PIPING, NOZZLE AND MANWAY FLANGED JOINTS

Fluid Service	Flange Design Conditions	Flange Design Conditions	Flange Facing	Gasket Type (8), (9), (10), (11)
	Primary (1) Rating Class	Temperature Range, ( F) (2)
Oil, Hydrogen Service, Hydrogen Rich Service (3) (4) (12)	150, 300	See Table 6	RF	Sheet, if approved by the Owner’s Engineer
Oil, Hydrogen Service, Hydrogen Rich Service (3) (4) (12)	150, 300, 600, 900,1500, 2500	Any	RF	Spiral Wound
Oil, Hydrogen Service, Hydrogen Rich Service (3) (4) (12)	600, 900, 1500, 2500	Any	RJ (12)	Ring (12)
Steam, Steam Condensate and Boiler Feed Water	150, 300	See Table 6	RF	Sheet, if approved by the Owner’s Engineer
Steam, Steam Condensate and Boiler Feed Water	150, 300, 600, 900, 1500, 2500	Any	RF	Spiral Wound
Steam, Steam Condensate and Boiler Feed Water	600, 900, 1500, 2500	Any	RJ (12)	Ring (12)
Air and Nitrogen	300 & Lower	300 & Below	RF	Sheet
Air and Nitrogen	300 & Lower	Above 300	RF	Spiral Wound
Water (Excluding Boiler Feed Water)	125,150, 250 (1)	150 & Below	FF (13)	Sheet
Water (Excluding Boiler Feed Water)	150	300 & Below	RF	Sheet
Fluid Solids (5)	300 & Lower	1200 & Below	RF	Spiral Wound
Toxic Fluids (6)	300 & Lower	750 & Below	RF	Spiral Wound
HF Acid	300 & Lower	750 & Below	RF	Spiral Wound(14)
Refrigerants and Refrigerated Hydrocarbons (7)	300 & Lower	-100 & 400	RF	Spiral Wound

NOTES:

Steel flange rating class in accordance with ASME/ANSI B16.5, Cast Iron flange rating in accordance with ASME/ANSI B16.1, and ductile iron flange ratings are in accordance with ASME/ANSI B 16.42.
Gasket design temperature shall be same as flange design temperature, see paragraph 4.4 for the flange design temperature.
Liquid, vapor or gas, except when in refrigerant service.
Metallic gasket components subject to Hydrogen Service will be specified by the Owner’s Engineer.
In suspension in any medium.
Includes fluids such as chlorine or hydrogen sulfide, contained in solutions or mixtures.
Includes propane, ethylene, ammonia, Freon, nitrogen, LNG.
Spiral wound gaskets to be in accordance with paragraph 5.3 and Table 4.
Ring joints gaskets shall be in accordance with paragraph 5.4 and Table 5.
Sheet gaskets to be in accordance with paragraph 5.5 and Table 6.
Sheet gaskets compatible with the fluid service shall be used on API–650 tank manway flanges.
Used for construction prior to May 1991 or to match existing flanges in any rating.
Flat face flanges and full face gaskets shall be used when mating against gray cast iron flanges.
Supplemental requirements are included in EP 5–10–1 for Phillips HF Units and EP 5–10–2 for UOP HF Units.

TABLE 3

LAP JOINT FLANGE STUB END THICKNESS REQUIREMENTS

Material (1)	Size	Minimum Thickness
Carbon Steel	NPS 2 to 4	Sch 160
Carbon Steel	NPS 6 to 8	Sch 80
Carbon Steel	NPS 10 or Larger	1/2 Inch
Stainless Steel	NPS 2 or smaller	Sch 80S
Stainless Steel	Larger than NPS 2	Sch 40S

NOTE:

(1) For materials not listed, subject to the approval of the Owner’s Engineer.

TABLE 4

SPIRAL WOUND GASKET REQUIREMENTS

Service	Gasket Specification
All services with Temperature Limitations of -100 to 850F in oxidizing environments, (not including chemical oxidizers) and -100 F to 1500 F in non– oxidizing environments.	Flexible graphite filled 0.175 inch thick spiral wound gasket per ASME B16.20 with a steel outer compression centering ring (1), and inner ring (2), (3). The flexible graphite shall be asbestos free and meet the following specifications: Density (Nominal) 70 lbs/ft3 ” 10 lbs/ft3
	Carbon Content 95 wt% min. Leachable Chlorides 100 ppm max. Total Sulfur 1000 ppm max. Fillers or Binders None
	The winding and inner ring materials shall be as follows:
	Reformer MOV Valves — AISI Type 316 Hydrofluoric acid — Monel 400(5) Hydrochloric acid — Monel 400 or Hastelloy C(4) Clad Pressure Vessels — Same Material as Cladding or Heat Exchangers All other Services — AISI Type 304 or 316
Chemical oxidizers (e.g. sul– furic, nitric, phosphoric acids) - 100 F to 500 F.	PTFE (Teflon) filled 0.175 inch thick spiral wound gaskets per API 601 with a steel outer compression centering ring (1) and inner ring (2), (3). The winding and inner ring material shall be as follows:
	Hydrofluoric acid — Monel 400(5) Sulfuric acid — Alloy 20 Phosphoric acid — AlSl Type 316 All other Services — AlSl Type 304 or 316
All other services	(*)Manufacturer’s Recommendation, requires approval of the Owner’s Engineer

NOTES:

The outer compression centering ring material shall be carbon steel, except for operating temperatures below -50 F and above 750 F, where the material of this ring shall be an austenitic stainless steel.
Inner rings shall be provided based on the following criteria.
For sizes NPS 12 and larger.
For all sizes when the temperature is less than -50 F, or when the temperature exceeds 1000 F.
For all sizes with a ASME/ANSI Class 900 or greater rating.
For all sizes in dirty or erosive services when specified by the Owner’s Engineer.
For all sizes when the design pressure is full vacuum.
In Hydrofluoric Acid (HF) Service, a teflon inner ring shall be supplied except when otherwise specified by the Owner’s Engineer.
For sizes NPS 10 and smaller in chemical oxidizer service, a PTFE inner ring shall be used.
Outer and inner rings are not required for flanges with a face designed to confine the gasket
Material selection depends on concentration of hydrochloric acid.
Supplemental requirements are included in EP 5–10–1 for Phillips HF Units and EP 5–10–2 for UOP HF Units.

TABLE 5

RING JOINT GASKET MATERIALS AND HARDNESS REQUIREMENTS

Plant	Flange Material	Gasket Material	Maximum Brinell Hardness
IPE	Carbon steel	Soft iron	90
IPE	Carbon steel	Low carbon steel	120
IPE	Low alloy ( 9 Cr)	5 Cr–1/2 Mo	130
IPE	AISI Types 304, 316, 321, 347	AISI Types 304, 316, 347	160
IPE	Monel	Monel 400 (1)	130
IPE	Other Materials	Same material as flanges	(3)

NOTES:

(1) Identification symbol of M400 shall be stamped on the gasket.

(3) (*)Requires approval of the Owner’s Engineer.

TABLE 6

SHEET GASKET REQUIREMENTS

Fluid Service (1)	Pressure Class (2)	Temperature Range ( F) (3)	Flange Facing	Thk. (in.)(9)	Gasket Specification
Hydrocarbon, Steam and Boiler Feed Water	150	Note (4)	RF	0.125	Flexible Graphite (5), (6) or Graphonic (7) Sheet Gaskets
Hydrocarbon, Steam and Boiler Feed Water	300	Note (4)	RF	0.125	Flexible Graphite (5), or Graphonic (7) Sheet Gaskets
Sour Water	125,150 250	150 & Below	FF	0.125	Flexible Graphite (5), (6), Graphonic (7), Viton or PTFE Sheet Gaskets
Sour Water	150	300 & Below	RF		Flexible Graphite (5), (6), Graphonic (7), Viton or PTFE Sheet Gaskets
Air and Nitrogen	300 & Lower	300 & Below	RF	0.125	Flexible Graphite (5), (6), Graphonic (7), PTFE, Viton, Aramid (Kelvar), Reinforced Nitrile, Neoprene Bound or Phenolic(8) Sheet Gaskets
Water (Excluding Sour and Boiler Feed Water)	125,150 250	150 & Below	FF	0.125	Flexible Graphite (5), (6), Graphonic (7), PTFE, Viton, Aramid (Kelvar), Reinforced Nitrile, Neoprene Bound or Phenolic(8) Sheet Gaskets
Water (Excluding Sour and Boiler Feed Water)	150	300 & Below	RF		Flexible Graphite (5), (6), Graphonic (7), PTFE, Viton, Aramid (Kelvar), Reinforced Nitrile, Neoprene Bound or Phenolic(8) Sheet Gaskets

NOTES:

(*)Sheet gaskets shall not be used in Hydrocarbon or steam service unless otherwise specified by the Owner’s Engineer; see Table 2 for recommended gaskets.
Steel flange rating class in accordance with ASME/ANSI B16.5, Cast Iron flange rating in accordance with ASME/ANSI B16.1, and ductile iron flange ratings are in accordance with ASME/ANSI B16.42.
Gasket design temperature shall be same as flange design temperature, see paragraph 4.4 for the flange design temperature, but not exceeding the temperatures listed in this table. Gasket design temperature and pressure shall not exceed the manufacturer’s pressure–temperature rating.
All services, excluding Hydrogen Service, with temperature limitation of-100 F to 850 F in oxidizing environments (not

including chemical oxidizers) and -100 F to 1500 F in non–oxidizing environments.

Flexible Graphite sheet gaskets shall be UCAR Grafoil GH–E or equivalent per the following specifications. All sheet gaskets shall be branded with the Manufacturer’s identification.

Nominal Density - 70 lbs/ft3 Asbestos Content - None

Carbon Content - 95 wt. % min. Leachable Chlorides - 100 ppm max. Total Chlorides - 500 ppm max. Total Fluorides - 300 ppm max.

Total Sulfur - 1000 ppm max. Reinforcing Insert - AISI Type 316, 0.005 in. thick tanged metal sheet

(*)If approved by the Owner’s Engineer, UCAR Grafoil GH–R or equivalent sheet gaskets per the following specification can be used. All sheet gaskets shall be branded with the Manufacturer’s identification.

Flexible Graphite - see Note (5) above

Reinforcing Insert - AISI Type 316, 0.002 inch thick sheet

The flexible graphite sheet shall be chemically bonded to the top and bottom of the metal insert by an adhesive layer not more than 0.0015 inches thick that will carbonize when subjected to heat.

Flexible graphite corrugated metal sheet gasket shall be M&P Graphonic or equivalent per the following specification. All sheet gaskets shall be branded with the Manufacturer’s identification.

Flexible Graphite - see Note (5) above

Reinforcing Insert - AISI Type 316, 0.024 inch thick corrugated steel ring

The flexible graphite sheet shall be chemically bonded to the top and bottom of the metal insert by an adhesive layer not more than 0.0015 inches thick that will carbonize when subjected to heat.

Phenolic gasket or equivalent electrical insulting gasket is to be used only at the flanged connection between the below ground to above ground plant water lines.
When approved by the Owner’s Engineer, 0.0625 inch thick. Sheet gasket may be used with new or like new flanges where design conditions approach the maximum pressure–temperature gasket rating.

TABLE 7

METAL JACKETED GASKET REQUIREMENTS

Service	Gasket Specification
Air and water service below 300F	1/8 inch thick double metal jacketed gasket per ASME B16.20 with elastomeric–bound filler material and 0.015 inch minimum thick jacket. Acceptable filler materials are QuinT Corp.“E– 6046”, or equivalent. Metal jacketing material should be as follows: Fresh and Salt Water — Copper or brass Sour Water — AISI Type 316L SS
All services, except chemical oxidizers, -20F to 1500 F	3/32 inch thick double metal jacketed gasket per ASME B16.20 with flexible graphite filler material and 0.015 inch minimum thick jacket. Flexible graphite filler specifications shall be as follows:
	Density (Nominal) 70 lbs/ft3 ” 10 lbs/ft3
	Carbon Content 95 wt% min. Leachable Chlorides 100 ppm max. Total Sulfur 1000 ppm max. Fillers or Binders None
	Metal jacketing material shall be as follows:
	Hydrofluoric acid — Monel 400
	Hydrochloric acid — Hastelloy C
	Clad and/or Weld — Use same material as cladding and/or overlay vessels overlay
	Hydrogen with H2S — AISI Types 304L, 316L, 321 or 347 SS at 450 F to 700 F
	Hydrocarbon with — AISI Type 316L, 317L SS Naphthenic acid at all temperatures

TABLE 7

METAL JACKETED GASKET REQUIREMENTS (CONTINUED)

Service	Gasket Specification	Gasket Specification	Gasket Specification	Gasket Specification
All services, except chemical oxidizers, -20F to 1500 F (Continued)	Remaining general services exceeding 700 F	Remaining general services exceeding 700 F	—	AISI Types 304L, 316L, 321, 347 SS
	Remaining general services up to and including 700F	Remaining general services up to and including 700F	— AISI Type 410S or 304L, 316L, 321, 347 SS Note: Carbon steel can be used if the expected corrosion allowance is less than or equal to 0.010 inches over the gasket’s expected life.	— AISI Type 410S or 304L, 316L, 321, 347 SS Note: Carbon steel can be used if the expected corrosion allowance is less than or equal to 0.010 inches over the gasket’s expected life.
Chemical oxidizers (e.g. sulfuric, nitric, phosphoric acids)	3/32 inch thick double metal jacketed gasket per API Standard 601 with PTFE (teflon) filler material and 0.015 inch minimum thick jacket. Metal jacketing shall be as follows:	3/32 inch thick double metal jacketed gasket per API Standard 601 with PTFE (teflon) filler material and 0.015 inch minimum thick jacket. Metal jacketing shall be as follows:	3/32 inch thick double metal jacketed gasket per API Standard 601 with PTFE (teflon) filler material and 0.015 inch minimum thick jacket. Metal jacketing shall be as follows:	3/32 inch thick double metal jacketed gasket per API Standard 601 with PTFE (teflon) filler material and 0.015 inch minimum thick jacket. Metal jacketing shall be as follows:
	Sulfuric acid	—	Alloy 20	Alloy 20
	Nitric acid	—	AISI Type 304 SS, use Type 304L SS for welded construction	AISI Type 304 SS, use Type 304L SS for welded construction
	Phosphoric acid	—	AISI Type 316 SS, use Type 31 6L SS for welded construction	AISI Type 316 SS, use Type 31 6L SS for welded construction

TABLE 8

SOLID FLAT METAL GASKET MATERIALS AND HARDNESS REQUIREMENTS

Flange Material	Gasket Material	Maximum Brinell Hardness (1)
Carbon steel	Soft iron	90
Carbon steel	Low carbon steel	120
Low alloy ( 5 Cr)	5 Cr–1/2 Mo	160
AISI Types 304, 316, 321, 347	AISI Type 304, 316	140
AISI Types 304, 316, 321, 347	AISI Type 347	150
Monel	Monel	130
Other austenitic steels and nonferrous materials	Same material as flanges	Subject to the approval of the Owner’s Engineer

NOTE:

(1) Materials are supplied in the annealed condition.

TABLE 9

REQUIRED MINIMUM THICKNESS FOR SOLID FLAT METAL GASKETS

Gasket Inside Diameter (inches)	Minimum Gasket Thickness (inches)
Less than 24	1/16
Greater than or equal to 24	1/8

TABLE 10

BOLT SELECTION FOR GENERAL SERVICE

Bolting Temperature Range ( F) (1)	Ferritic Flanges (2)	Ferritic Flanges (2)	Austenitic Flanges (2)	Austenitic Flanges (2)
Bolting Temperature Range ( F) (1)	Bolts	Nuts	Bolts (5)	Nuts
-425 to -151	—	—	A320 Gr B8 Cl.2 (6)	A194 Gr 8A
-150 to -21	A320 Gr L7	A194 Gr 4	A320 Gr B8 Cl.2(5)	A194 Gr 8A
-20 to 800	A193 Gr B7	A194 Gr 2H	A193 Gr B7	A194 Gr 2H
-20 to 800	A193 Gr B16	A194 Gr 4	A193 Gr B16	A194 Gr 4
-20 to 800	A193 Gr B16	A194 Gr 4	A193 Gr B8M Cl.2(5)	A194 Gr 8A
801 to 1000	A193 Gr B16	A194 Gr 7	A193 Gr B16(5)	A194 Gr 7
801 to 1000	A193 Gr B16	A194 Gr 7	A193 Gr B8M Cl.2(3),(5)	A194 Gr 8A
1001 to 1500	—	—	A193 Gr B8M Cl.1(4)	A194 Gr 8A

NOTES:

(*)For uninsulated flanges, the bolt temperature for this table may be taken as 80% of the fluid temperature. A lower bolt temperature may be used if determined by test or heat transfer calculations and approved by the Owner’s Engineer.
Bolt materials for pressure vessel and heat exchanger girth flanges, and other pressure vessel components shall be in accordance with the ASME Code, Section II (eg. SA–320, SA–193, and SA–194).
A453 Gr 660 Class A or B bolting may be used if higher strength bolting is needed for austenitic flanges with temperatures between 800 F and 1000 F.
ASME/ANSI 16.5 classifies A193 B8M Class 1 as low–strength bolting, limits them to Classes 150 and 300, and requires that nonmetallic gaskets be used. ASME/ANSI B16.5 recommends difficult–to–contain fluids and flanged joints with low–strength bolting operating above 400 F to be derated (25%) to reduce the possibility of leakage and the need to retighten.
Solution treated and strain hardened. Maximum bolt temperature is limited to 1000 F.
(*)Other Class 1 grades of austenitic bolting made to A193 and A320 are categorized by ASME/ANSI 16.5 as low–strength bolting. Use of this bolting and other bolting not in the above table requires prior approval from the Owner’s Engineer.

TABLE 11

BOLT SELECTION FOR SCC SERVICE

Service	Bolting Temperature Range(1) ( F)	Ferritic Flanges(2)	Ferritic Flanges(2)
Service	Bolting Temperature Range(1) ( F)	Bolts	Nuts
HF ACID(3)	-20 to 850	A193 Gr B7M (4)	A194 Gr 2HM
Other SCC Services(4)	-20 to 800	A193 Gr B7M	A194 Gr 2HM
Other SCC Services(4)	801 to 1000	A193 Gr B16	A194 Gr 4

NOTES:

(*)For uninsulated flanges, it substantiated by heat transfer calculations and approved by the Owner’s Engineer, the bolt temperature for this table may be taken as 80% of the vessel design temperature.
Bolt materials for pressure vessel and heat exchanger girth flanges, and other pressure vessel components shall be in accordance with the ASME Code, Section II (eg. SA–193 and SA–194)
Supplemental requirements are included in EP 5–10–1 for Phillips HF Units and EP 5–10–2 for UOP HF Units.
If bolts are immersed in hydrofluoric acid, they shall be specified to be K–Monel to ASTM F468, UNS No 5500.
Stress corrosion cracking environment of low alloy carbon steel bolting.

© 2026 Inflection Point Engineering, LLC. All rights reserved. The content of this page — including calculation methods, reference data, written analysis, interactive tools, and source code — is the intellectual property of Inflection Point Engineering, LLC and is protected under applicable copyright, trademark, and trade secret laws. Unauthorized reproduction, redistribution, modification, or derivative use in whole or in part is prohibited without prior written consent.

Disclaimer. This material is provided for informational and educational purposes only and does not constitute professional engineering advice. Calculations, reference data, and methodologies are based on published standards and accepted engineering practice but are not a substitute for engineering judgment, site-specific analysis, or review by a licensed Professional Engineer. Inflection Point Engineering, LLC makes no warranties, express or implied, regarding the accuracy, completeness, or fitness for a particular purpose of any content presented here, and shall not be liable for any direct, indirect, incidental, or consequential damages arising from its use. Users assume all risk associated with applying this content to real-world design, operations, or decisions.