Diseño Tanques

SCOPE

I 1.1 This practice covers the design, size, quantity, and location of accessories for atmospheric fixed roof and

floating roof storage tanks and open top storage tanks.

I 1.2 The requirements for refrigerated storage tanks and vessels are not covered by this practice.

I 1.3 An asterisk (
) indicates that either a decision by the Owner's Engineer is required, that additional

information is to be furnished by the Owner's Engineer, or that information for Owner's Engineer approval

is to be supplied by the vendor or contractor.

SUMMARY OF ADDITIONAL REQUIREMENTS

I 2.1 Table 1 lists the practice and standards which shall be used with this practice.

I
2.2 Table 2 lists the practices and standard which shall be used with this practice as specified by the

Purchaser.

TABLE 1

PRACTICE

IP 15-1-3 Instruments for Storage Tanks and Vessels

STANDARDS

API Standard

650 Welded Steel Tanks for Oil Storage

RP-2003 Recommended Practice for Protection Against Ignitions Arising Out of Static, Lightning

and Stray Currents

ANSI Standard

A 1264.1 Safety Requirements for Workplace Floor and Wall Openings, Stairs, and Railing

Systems

TABLE 2

PRACTICES

IP 3-2-2 Foam Systems for Storage Tanks

IP 3-2-7 Manual Sampling Systems

IP 3-16-1 Flanged Joints, Gaskets and Bolting

IP 9-7-3 Vents for Fixed Roof Atmospheric Storage Tanks

IP 14-1-1 External Insulation

STANDARD

ANSI Standard

A 14.3 Safety Requirements for Fixed Ladders

TANK CONNECTIONS

LOCATION OF ATTACHMENTS

O,R
3.1 Unless otherwise specified, the location of principal connections and attachments for fixed roof

tanks shall be per Figure 1. The location of shell nozzles and manholes for floating roof tanks shall

be per Figure 2. The requirements for and the location of other tank connections and appurtenances will

be specified.

Changes shown by

IP 9-7-1 Accessories for Atmospheric Storage Tanks

Page 2 of 12

Rev. 1 March 1998 (This practice is appropriate for attachment to Inquiry or Purchase Document)

THIS INFORMATION FOR AUTHORIZED COMPANY USE ONLY

EXXON RESEARCH AND ENGINEERING COMPANY — FLORHAM PARK, N.J.

INTERNATIONAL

PRACTICE

ROOF AND SHELL MANHOLES

M 3.2 The minimum number and size of shell and roof manholes shall be per the following:

NOMINAL NUMBER AND SIZE OF MANHOLES

TANK SHELL ROOF

DIAMETER

All Tank Types Fixed Roof Tanks Floating Roof Tanks (1)(2)

ft m Number in. mm Number in. mm Number in. mm

10 - 20 3 - 6 1 30 750 1 24 600 1 30 750

> 20 - 60 > 6 - 18 1

1

24

30

600

750

2 24 600 1 30 750

> 60 - 90 > 18 - 27 1

1

24

30

600

750

2 24 600 2 30 750

> 90 > 27 2

1

24

30

600

750

2 24 600 2 30 750

Notes:

(1) In addition, floating roofs shall be provided with at least one 20 in. (500 mm) manhole for each pontoon

compartment.

(2) Where two deck manholes are required, they shall be located at diametrically opposite positions.

Manhole requirements for internal floating roofs are specified in IP 9-7-4.

MANUAL GAUGING - SAMPLING FOR FIXED ROOF TANKS

S,O
3.3 Fixed roof tanks (with or without internal floating covers). A manual gauging-sampling well per

Figure 4 shall be used where the stored product, including intermediate storage, is specified as a “static

accumulator." Gauge well shall be burr-free.

A gauging-sampling well is not required where the stored product will not be a “static accumulator." In

such cases, a gauge hatch shall be installed on a roof manhole cover.

R
3.4 If a manhole or a separate roof connection is used for gauging-sampling purposes it shall be

located near a roof support.

O 3.5 Gauging hatches shall be per the following:

a. The gauging hatch shall have a seal with corrosion resistant seats suitable for a pressure of 2 oz/sq

in. (0.86 kPa) or design pressure of tank whichever is greater, and a heavy stay-back cover.

b. The gauging hatch shall be of 8 in. (200 mm) minimum diameter.

c. The cover shall weigh at least 6-1/2 lb. (3 kg).

d. Larger hatches shall have the same minimum weight (mass) per unit area.

WATER DRAWOFF CONNECTIONS

O

3.6 Water drawoff connection. Tanks in hydrocarbon service shall be provided with a minimum of one

water drawoff connection, using the API Low Type shell nozzle. Water drawoff’s for tanks in other

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