Hydrostatic Test (API 650 7.3.6–7.3.8)

Identification

Company

Tank ID

Location

Record Type

Units and rule set

Switching converts what is typed in and changes the rule set to the printed US values (12 / 18 / 9 in./h, 32 ft spacing, 1/2 in. per 32 ft). Calculations and saved records stay in SI.

Lists this tool’s records, including those saved with the earlier Hydrotest Filling Procedure calculator.

Summary of checks

Enter the tank and the test level to see the checks.

1. Tank and Test Water Level (7.3.6.1, 7.3.6.2)

Tank

Maximum test height from API 653 4.3.3.2 m · Shell Evaluation tool · blank = no limit

Fills the 4.3.3.2 maximum test height (and D and H when blank) and the Figure 5.2 box below; edit any of them afterwards.

Nominal diameter, D m

Shell height m

Maximum design liquid level, H m · blank = shell height

Roof

Test water level

Roof-to-shell weld elevation m · blank = shell height

Water is not sufficient and the Purchaser specifies a hydrostatic test exemption (7.3.6.2.2)

Levels c) and d) are compared with level a). Where the test level is below the full level, the shell joints above the water must be examined by 7.3.6.2.1. Annex F tanks are tested to Annex F, not here.

1A. Existing Tank: Is a Hydrostatic Test Required? (API 653 12.3)

Work done on the tank

Test or exemption (12.3.3)

Major repair or alteration (API 653 3.25): a shell penetration over DN 300 (NPS 12) below the design liquid level; a bottom penetration within 300 mm (12 in.) of the shell; a shell plate below the design level or annular plate replaced or added over 300 mm (12 in.) long; over 300 mm of vertical shell or radial annular weld replaced; a new bottom (part of one under 12.3.4.3 is not); shell-to-bottom weld replaced beyond 12.3.3.5.1 a); jacking the shell.

12.3.3.2: both are needed for any exemption.

a) Repair reviewed and approved by an engineer experienced in API 650 tank design, who concurs in writing with the exemption b) The owner/operator has authorized the exemption in writing

What the repair includes:

Shell repair: welds to existing shell, new plate, door sheets, nozzles (12.3.3.3) Annular ring or bottom plate repair within the critical zone (12.3.3.4) Shell-to-bottom weld repair (12.3.3.5) Minor shell jacking (12.3.3.6)

Existing material in the repair area (12.3.3.3.3)

Bottom of the repair above the tank bottom m

Tank fill height m · blank = H

Shell thickness at the repair mm

Product specific gravity, G

Shell-to-bottom weld repair (12.3.3.5.1)

Longest fully replaced length mm

Closest spacing of repairs over 50 % mm · incl. opposite side

Shell falls in the safe-for-use area of Figure 5.2

Subgrade under the new plates acceptable to the authorized inspector, or restored to that condition With an annular ring: the ring and its support remain intact. Without one: no welding on the remaining bottom in the critical zone, and the shell and bottom support there remain intact

Documented service history of acceptable settlement, and none expected in the test: no settlement survey (12.5.1)

2. Filling Rates and Schedule (7.3.7.6)

Settlement measurements waived by the Purchaser (Data Sheet Line 14)

Procedure

Bottom shell course thickness mm

Top shell course width m · used under 22 mm

Fill pump rate m³/h

Emptying rate m³/h

Venting limit on filling, 5.8.5 mm/h · optional

Purchaser minimum fill rate mm/h · Data Sheet Line 23

Hold at test height before reading set 5 h · at least 24

Filling stopped for each reading set h · 0 = keep filling

The Purchaser may extend the hold at the test height (7.3.7.6 b 5) when:

i. the tank is the first one in the area ii. it is larger than any other tank in the area iii. its unit bearing load is higher than any other tank in the area iv. the rate or size of settlement is in question

With settlement measurements, the maximum rates are 300 mm/h (12 in./h) in the top course and 460 mm/h (18 in./h) below it when the bottom course is under 22 mm (7/8 in.); otherwise 460 / 300 / 230 mm/h (18 / 12 / 9 in./h) in the bottom, middle and top thirds of the shell. The rate used in each band is the lowest of these, the venting limit, the OISD stage rate and the pump.

3. Settlement Survey (7.3.7.6, 7.3.7.9)

Purchaser omits reading sets 2, 3 and 4 (7.3.7.6 Note)

Set	When	Water level m

4. Settlement Readings Check (7.3.7.7)

Enter the settlement at each shell point since reading set 1, downward positive. Filling stops and the Purchaser is told if the mean exceeds 50 mm (2 in.), or the difference between neighbouring points exceeds 13 mm per 10 m (1/2 in. per 32 ft) of circumference.

Point	Position	Settlement mm	To next, per 10 m mm

Opens the Tank Settlement tool (API 653 Annex B cosine fit) with these points as elevation changes in ft, settling points negative.

5. Test Water and Temperature (7.3.7.4, 7.3.7.5, S.4.10, X.4.10)

Shell material

Test water

Lowest shell metal temperature in the test °C

Design metal temperature °C · Figure 4.1

6. Test Procedure and Record (7.3.6 – 7.3.8)

Tick each item once it is confirmed. Items that don’t apply are hidden.

Save & Report

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