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MIL-S-901D establishes high-impact shock testing requirements for shipboard machinery, equipment, systems, and structures. The testing is designed to evaluate the ability of shipboard equipment to withstand severe mechanical shock conditions associated with naval service.

Clark Testing has a long history supporting MIL-S-901D shipboard equipment qualification, with specialized medium weight shock testing capabilities at our Jefferson Hills, Pennsylvania facility.

Clark’s NAVSEA-approved MIL-S-901D medium weight shock stand is capable of testing equipment in multiple mounting configurations. The system uses a pendulum and hammer configuration with a 3,000-pound hammer striking the base of the test frame and can accommodate test articles weighing up to 7,000 pounds. Clark Testing

MIL-S-901D Medium Weight Shock Testing

MIL-S-901D shock testing is used to evaluate shipboard equipment subjected to high-impact mechanical shock. Equipment qualification depends on the function of the equipment, its installation aboard the ship, mounting arrangement, and the applicable shock classification.

MIL-S-901D testing includes lightweight, medium weight, and heavyweight test categories. Clark specializes in medium weight MIL-S-901D shock testing and has supported naval equipment qualification programs for decades. Clark Testing

Clark’s shock testing capabilities can support a variety of equipment configurations and qualification programs where medium weight MIL-S-901D testing is applicable.

MIL-S-901D Grade A and Grade B Equipment

MIL-S-901D separates shipboard equipment into shock grades based on the equipment’s importance to ship operation and the consequences of failure during a shock event.

Grade A equipment includes items essential to the safety and combat capability of the ship.

Grade B equipment includes equipment whose continued operation is not essential to combat capability, but whose failure could create a hazard to personnel, the ship, or Grade A equipment. Clark Testing

Determining the appropriate grade is an important part of establishing the shock qualification requirements for a test article.

MIL-S-901D Equipment Classes

MIL-S-901D also classifies equipment according to its shipboard mounting requirements and whether resilient or isolation mounting is used.

Class I equipment is required to meet applicable shock requirements without resilient or isolation mountings.

Class II equipment uses resilient mountings to meet the applicable shock requirements.

Class III equipment may be installed either with or without resilient mountings and therefore must address the requirements applicable to both Class I and Class II configurations. Clark Testing

The intended shipboard installation and mounting configuration should be considered when developing the test setup.

MIL-S-901D Type A, Type B and Type C Testing

MIL-S-901D further categorizes testing according to the relationship between the test article and the larger shipboard system.

Type A testing applies to a principal unit or major component directly supported by the ship structure. Examples can include generator sets, air-conditioning equipment, launchers, and certain valves.

Type B testing applies to a subsidiary or secondary component that is not itself a principal unit but may support or form part of a principal system.

Type C testing applies to a subassembly that forms part of a principal unit or subsidiary component. Clark Testing

Correctly identifying the grade, class, type, mounting arrangement, and intended installation helps establish the appropriate MIL-S-901D test configuration.

Clark Testing MIL-S-901D Capabilities

Clark Testing’s history with naval shock qualification extends back through the former Westinghouse Advanced Energy Systems operations in Western Pennsylvania. Clark’s existing MIL-S-901D shock stand was among the early shock-test systems installed in the United States for naval equipment qualification. Clark Testing

Today, Clark provides dedicated MIL-S-901D medium weight shock testing using its NAVSEA-approved facility and equipment.

Capabilities include:

• MIL-S-901D medium weight high-impact shock testing
• Test articles weighing up to 7,000 pounds
• 3,000-pound pendulum/hammer shock system
• Multiple equipment mounting configurations
• Grade A and Grade B equipment testing
• Class I, Class II, and Class III configurations, as applicable
• Type A, Type B, and Type C equipment evaluations
• Support for shipboard equipment qualification programs

For additional facility and equipment information, visit Clark Testing’s Medium Weight Shock Testing capabilities page.

MIL-S-901D and MIL-DTL-901E

MIL-S-901D was issued on March 17, 1989. MIL-DTL-901E, issued June 20, 2017, superseded MIL-S-901D. The current E revision was subsequently reviewed and validated for acquisition use in December 2023. QuickSearch

MIL-S-901D nevertheless remains relevant to existing equipment, legacy qualification programs, drawings, specifications, and contractual requirements. The current MIL-DTL-901E also specifically recognizes previously approved testing performed under MIL-S-901C, MIL-S-901D, MIL-S-901D with Interim Changes, and MIL-DTL-901E as potential candidates for qualification by extension, subject to the required technical review, approval, and documentation. QuickSearch

Because the applicable specification and qualification path depend on the individual program, customers with requirements referencing MIL-DTL-901E should contact Clark Testing to review the specific equipment, existing qualification history, and test requirements before determining the appropriate approach.

Why MIL-S-901D Shock Testing Matters

Equipment installed aboard naval vessels can experience severe mechanical shock. MIL-S-901D qualification provides a standardized means of evaluating whether shipboard equipment can withstand the applicable high-impact shock environment without creating unacceptable equipment, personnel, or ship safety risks.

The specification’s combination of equipment grades, classes, test types, mounting requirements, and shock-test categories allows qualification testing to reflect the equipment’s actual function and intended shipboard installation.

For manufacturers and suppliers working with naval equipment, understanding these classifications early in a program can help establish an appropriate test configuration before equipment arrives at the laboratory.

MIL-S-901D Testing at Clark

Clark Testing combines specialized shock equipment with decades of experience supporting naval and shipboard equipment programs.

Customers preparing for MIL-S-901D testing can work with Clark to review the test article, mounting configuration, equipment classification, and applicable test requirements before testing begins.

For additional information about Clark’s facility, visit our MIL-S-901D Medium Weight Shock Testing page.

Have a MIL-S-901D shock testing requirement? Contact Clark Testing to discuss your equipment and qualification program or request a quote.

Frequently Asked Questions

What is MIL-S-901D?
MIL-S-901D is the 1989 revision of the U.S. military specification covering high-impact shock testing requirements for shipboard machinery, equipment, and systems. The Navy-hosted copy you provided is the appropriate primary reference for the D revision, although that server currently blocks automated retrieval.

Does Clark Testing perform MIL-S-901D shock testing?
Yes. Clark operates a NAVSEA-approved MIL-S-901D medium weight shock stand at its Jefferson Hills facility. The stand uses a 3,000-pound hammer and can accommodate test articles weighing up to 7,000 pounds. Clark Testing

What are Grade A and Grade B under MIL-S-901D?
Grade A identifies equipment essential to ship safety and combat capability. Grade B covers equipment that is not essential to combat operation but whose failure could create hazards to personnel, the ship, or Grade A equipment. Clark Testing

What is the difference between MIL-S-901D and MIL-DTL-901E?
MIL-S-901D is the 1989 D revision. MIL-DTL-901E was issued in 2017 and superseded MIL-S-901D. MIL-DTL-901E remains the active specification and was validated for continued acquisition use in 2023. QuickSearch

Can previously qualified MIL-S-901D equipment be considered under MIL-DTL-901E?
MIL-DTL-901E provides a process for extension of previously approved shock tests. It specifically identifies items previously qualified under MIL-S-901D among potential extension candidates, but this requires appropriate review, approval, documentation, and consideration of differences in the equipment and shock environment.