scope:

This specification covers shock testing requirements for ship board machinery, equipment, systems, and structures, excluding submarine pressure hull penetrations, (see 1.2.5). The purpose of these requirements is to verify the ability of shipboard installations to withstand shock loadings which may be incurred during wartime service due to the effects of nuclear or conventional weapons.

Tests shall be classified in accordance with one of the following test categories, as specified (see 3.1.2 and 6.2.1): Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Commander, Naval Sea Systems Command, SEA 55Z3, Department of the Navy, Washington, DC 20362-5101 by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter.

Lightweight. The lightweight test is a test performed on the lightweight shock machine (see figure 1).

Medium weight. The medium weight test is a test performed on the medium weight shock machine (see figure 2).

Heavyweight. The heavyweight test is a test performed on a standard or large floating shock platform (see figures 3 and 4).

Items to be tested shall be classified in accordance with one of the following grades, as specified (see 3.1.3 and 6.2):

Grade A. Grade A items are items which are essential to the safety and continued combat capability of the ship.

Grade B. Grade B items are items whose operation is not essential to the safety and combat capability of the ship but which could become a hazard to personnel, to grade A items, or to the ship as a whole as a result of exposure to shock.

Items to be tested shall be classified in accordance with one of the following classes, an specified (see 3.1.4 and 6.2):

Class I. Class I equipment is defined as that which is required to meet these shock requirements without the use of resilient mountings installed between the equipment and the ship structure or foundation.

Class II. Class II equipment is defined as that which is required to meet these shock requirements with the use of resilient mountings installed between the equipment and the ship structure or shipboard foundation.

Class III. Unless otherwise specified (see 3.1.6.3(e)), class III equipment is defined as that which has shipboard application both with and without the use of resilient mountings and is therefore required to meet both class I and class II requirements.

Tests shall be classified in accordance with one of the following types, as specified (see 3.1.5 and 6.2):

Type A. A type A test is a test of a principal unit. This is the preferred test. Principal units are items which are directly supported by the ship structure or by a foundation which is directly attached to the ship structure, and items mounted in piping systems, ducting systems, and similar systems which are supported by ship structure. The shock response of a principal unit is primarily a function of the rigidity and mass of the item and the shipboard mounting structure, the shipboard mounting location, and the configuration of the item. Such items typically include diesel-generator sets, air conditioning plants, switchboards, radio transmitters, steam generators, missile launchers, and valves (if installed in piping which is supported by ship structure).

Type B. A type B test is a test of a subsidiary component. Subsidiary components are items which are the major parts of a principal unit. The shock response of the subsidiary component is significantly affected by that of the associated principal unit and all associated subsidiary components. The shock responses of the associated principal unit and all associated subsidiary components are significantly affected by that of the subsidiary component. Examples are the diesel engine of a diesel-generator set, the electric motor of an air conditioning unit, or the power supply section of a radio transmitter.

Type C. A type C test is a test of a subassembly. Subassemblies are items which are a part of a principal unit or a subsidiary component. The shock response of the subassembly is significantly affected by that of the associated principal unit or subsidiary component, but the shock response of the principal unit or subsidiary component is not significantly affected by the subassembly. Examples are thermometers, gauges, meters, relays, and resistors. The distinction between subassembly and assembly or part as used herein may be different than that used in various equipment specifications or other acquisition documents.

Items shall be classified in accordance with one of the following mounting locations aboard ship, as specified (see 6.2):

Hull mounted. Hull mounted items are those mounted on:

For surface ships. The main structural members of the ship including structural bulkheads and structural bulkhead stiffeners below the main deck, and shell plating above the waterline.

For submarines. The main structural members of the ship including,hull frames, structural bulkheads, and structural bulkhead stiffenrers.

Deck mounted. Deck mounted items are those mounted on:

For surface ships. Main deck and above, and decks, platforms. and non-structural bulkheads below the main deck.

For submarines. Decks, platforms, and non-structural bulkheads.

Shell mounted. Shell mounted items are those mounted on:

For surface ships. The shell plating below the waterline.

For submarines. The shell plating. (This specification does not cover underwater explosion testing of items which penetrate the submarine pressure hull (see 1.1).)

Wetted-surface mounted. Wetted-surface mounted items are those mounted:

For surface ships. External to the hull and below the waterline.

For submarines. External to the pressure hull.

Items shall be classified in accordance with one of the following planes of mounting aboard ship, as specified (see 6.2):

Base

Front or face

Back

Top

Combination.(such as base and back)

Other

Items shall be classified in accordance with one of the following intended orientations aboard ship, as specified (see 6.2):

Unrestricted as to orientation aboard ship Restricted

Shaft, front, face, principal axis, and so forth, parallel to fore-and-aft axis of ship

Shaft, front, face, principal axis, and so forth, perpendicular to fore-and-aft axis of ship Other

intended Use: