scope:

Introduction

Aim

The aim of this Section of the Defence Standard is to provide advice on the selection of EMC requirements for all military equipment's and the application of Def Stan 59-41 throughout all phases of procurement and in-service use. It concentrates this advice under the following headings:

(a) The Operational Scenario and the Electromagnetic Environment.

(b) EMC Contractual Requirements.

(c) Control and Monitoring of EMC.

(d) Tailoring and Selection of Tests and Limits.

(e) Total System Trials.

(f) Improvement Programmes.

(g) In-service Maintenance and Change of Role.

To cater for the singular interests of Systems Controllerates, their special requirements are included in separate chapters two, three and four.

Should additional advice be required, this can be obtained from the MOD or DRA EMC specialist areas as given in the appropriate Systems Controllerate chapter. There are also several commercial EMC Test Houses which can advise, as many of these offer a comprehensive consultancy service. When specialists are not available within a Defence Contractor's organization, they should be encouraged to seek outside EMC specialist advice, throughout all stages of the project.

Objective of Defence Standard 59-41

The aim of Defence Standard 59-41 is to standardize the EMC management and control procedures and equipment level EMC test methods and limits across the three Systems Controllerates. The main objective is that, by the application and meeting of this Standard the contractor should be able to provide an acceptable level of visibility, during the early stages of the project, that total system compatibility would eventually be achieved and maintained throughout the equipment's in-service life.

Since the three System Controllerates have yet to establish any standardized procedures for total system testing, or acceptance criteria, the scope of this Standard cannot be extended to include standardized total system trials. Such trials are nevertheless essential to demonstrate that the fundamental requirements of self compatibility and compatibility with the EM environment are achieved by the contractor. Although Part 4 of this Standardis entitled "Open Site Testing", it currently only covers equipment level test requirements, when, for practical reasons, the Equipment Under Test (EUT) cannot be accommodated within a screened enclosure.

As this Standard now has the agreement of EMC specialists within the three Systems Controllerates it is expected that there will no longer be a need for separate Departmental Standards, at least in the field of equipment level EMC. This Standard should therefore be universally applied and invoked by all project specifications, when relevant.

This standardization of equipment level EMC test requirements across the three System Controllerates has re-introduced the concept of tailoring. Consequently, the Prime Contractor, who is usually the Design Authority, should, in consultation with the Project Manager, select the appropriate equipment level test limits and frequency ranges from Part 3 of this Standard, in accordance with the operational scenario and the electromagnetic environments envisaged for the total system when in service.

Although total system tests have not been included in this Standard such tests are essential to prove operational compatibility in the in-service environment and should be defined by the Prime Contractor to the satisfaction of the Project Manager.

Part 2 of this Standard stresses the need for the implementation of essential management and planning procedures to control all EMC aspects of the project, including resources, timescales and costs. These should apply at all stages of the project from feasibility through design and development to acceptance and on through production, PDS and in-service support.