5.1 Sounding tubes may be fabricated from 1¹/₂ NPS or larger. Only when otherwise specified, Schedule 40 components, manufactured from the list of material indicated in Practice F1155 and Specification A53/A53M, Grade S or Grade ERW. In addition, sounding tubes may be fabricated in stainless steel for stainless steel tanks.

5.1.1 Sounding tubes passing through or terminating in fuel tanks, potable water tanks, or clean salt water ballast tanks should be constructed of 70-30 copper nickel, but other suitable material is acceptable.

5.2 Striker plates shall be fabricated in accordance with Specification A36/A36M.

5.3 The fittings shall be designed in accordance with ASME B16.5, ASME B16.9, ASME B16.28, or ASME B16.11 as applicable (see Table 21 in Practice F1155), and the installation shall be in accordance with ASME B31.1 as modified by Specification F722. These standards cover the fitting tolerances.

5.4 Some cargo may preclude the use of materials specified in this guide. However, configuration examples are applicable for all applications.

5.5 When a sounding tube is combined with the air escape, either three 1¹/₄-in. (approximately 30-mm) diameter holes approximately 12 in. (305 mm) from the tank top equally spaced or six ¹/₂-in. (approximately 15-mm) diameter holes approximately 6 in. (150 mm) from the tank top equally spaced can be used for perforations. See Fig. 2.

5.6 Figs. 1-4 are guidance details.

FIG. 1 Type I Sounding Tube

FIG. 2 Type II Sounding Tube

FIG. 3 Type III Sounding Tube

FIG. 4 Type IV Sounding Tube

1.1 This guide covers design and construction criteria for striker plates and sounding tubes, excluding deck penetrations and caps, for use with sounding rods or tapes in freshwater, saltwater, and oil tanks.

1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.