The purpose of this Standard is to provide guidance on the measurement of impulse noise from MWEP and selection of hearing protection to demonstrate compliance with the requirements of CNAWR/CNAW(NI)R/MSFV(CNAW)R. 

This Standard may be used by a MOD Tasking Authority in contracts and by MOD and external noise specialists measuring impulse noise from MWEP. These measurements may then be used by risk assessors to determine associated risks to human hearing, acceptable levels of exposure and control measures that may be appropriate/required. 

MOD arrangements for policy, code of practice and guidance on the implementation of legislation are published in Joint Service Publication (JSP) 375, Management of Health and Safety in Defence. This Standard has been developed cognisant of this and HSE guidance. 

This Standard does not specify other measurements that may be required, for example for the measurement of overpressure to compare with national standards for human tolerance to muzzle blast. 

For the purpose of this Standard, guidance from BS EN 458:1994 has been has been adapted for use by the MOD for MWEP as the guidance provided by later versions (eg BS EN 458:2004) is limited to generic classifications such as "rifle" and therefore is not sufficiently refined to be applied to the range of noise sources associated with MWEPs. 

Consideration must be given to other appropriate, civil and Defence Standards and regulations particularly where specific test and measurement requirements are defined. 

This Standard is sponsored by the DE&S Director Technical through the Chair of the Safety Standards Review Committee. 

The MOD methodology used in the Standard has been validated by the Health and Safety Laboratory, a Directorate of the HSE. Copies of the validation can be made available for internal MOD use, where necessary for assurance purposes. 

The Tasking Authority must ensure the appropriate commercial requirements are included in the Contract. In particular that any security classification or protection necessary for the Contractors, or for documentation to be provided or delivered, meets the requirements of JSP 440.