The UK’s Department for Communities and Local Government has launched a specification for USAR personal protection equipment for high dust and CBRN environments.
Published: 09 December, 2010
The document Urban search and rescue personal protective equipment specification for high dust and chemical, biological, radiological, nuclear environments has been compiled by the Health and Safety Laboratory.
The report begins by outlining how USAR operations are divided into three separate scenarios:
Scenario 1
Level 2 (minor/significant) structural collapse (and possibly the lower end of Level 3 without hazardous material (HAZMAT) contamination), with no exceptional contamination by chemical, radioactive or microbiological substances. Moderate levels of airborne and settled dust without enhanced concentrations of highly hazardous or toxic components can be expected, together with the mechanical, thermal, electrical and climatic hazards inherent in USAR activity.
Scenario 2
Level 3 (major) and Level 4 (catastrophic) collapse without either HAZMAT or chemical, biological, radiological, nuclear (CBRN) contamination. Concentrations of airborne and settled dusts may be exceptionally high, and as a result potential exposures to the inherent low hazard components of the dust reach damaging concentrations.
Scenario 3
Level 3 (major) or Level 4 (catastrophic) collapse with either or both of HAZMAT and chemical, biological, radiological, nuclear (CBRN) materials present.
The Health and Safety Laboratory has extended the existing specification for USAR personal protective equipment (which broadly covers Scenario 1), to cover Scenarios 2 and 3 (Vaughan et al 2007a, 2007b), and assessed options for enhancing current USAR PPE (Webb et al, 2008) for:
- hazards generated in large scale dust clouds arising from building collapse (Scenario 2); and
- hazards from the release of toxic materials, including chemical, biological and radiological materials, with structural collapse (including those hazards generated in large scale dust clouds arising from building collapse) (Scenario 3)
The report draws on the work and develops a stand-alone, performance-based specification for PPE ensembles for Scenario 3.
It is envisaged that the specification will assist manufacturers, certification bodies and procurement authorities in producing and sourcing appropriate PPE for these applications.
The report notes that the protection factors for Scenario 3 exceed those required for high dust alone, so PPE for Scenario 3 should offer the more than adequate protection for Scenario 2 (high dust). “However, personal protective equipment for Scenario 3 may be more of a physiological and ergonomic burden than is necessary for Scenario 2. In addition, personal protective equipment for Scenario 3 should also be suitable for chemical, biological and radiological materials and HAZMAT incidents without high dust levels.”
The key feature of the specification is that a skin protection factor of 1,000 and a respiratory protection factor of 10,000 are required from a PPE ensemble if it is to be considered suitable for high dust and chemical, biological and radiological materials Scenario 3.
The type of PPE and respiratory protective equipment which provides this protection is relatively open, as long as it is capable of delivering the required level of protection, which mirrors the operational requirements in BS 8467 and 8468. The usual adequacy and suitability aspects (oxygen deficiency, confined spaces, required mobility, required working duration) will determine whether breathing apparatus or filtering devices are appropriate for a given operational scenario.
The specifications for individual items of personal protective equipment ensure that each individual item is capable of the performance required to form part of such an ensemble. There are two main reasons for these individual item specifications:
- to allow procurers and manufacturers/suppliers to assess the suitability of COTS equipment for inclusion in ensembles; and
- to allow procurers and manufacturers/suppliers to screen new equipment designs for their suitability for inclusion in ensembles without running full ensemble tests.
Using individual item specifications as a filter for equipment to be included in PPE ensembles is well established in its selection and procurement.
Having established that individual items are capable of the performance required to form part of an ensemble, the specification then gives performance requirements for the ensemble. These requirements cover not only protection, but also the suitability of the ensemble for likely USAR work tasks (including ergonomic and physiological considerations). The ensemble specification uses principles and reasoning from BS 8469:2007 “Personal protective equipment for firefighters – assessment of ergonomic performance and compatibility – requirements and test methods”, adapted to be more specific to USAR applications.
One particularly important advantage of ensemble testing is that it can generate simulated workplace protection factors (SWPFs).
In a SWPF test, the measured levels of protection may be taken as representative of likely workplace protection, and will supersede any generally accepted or assigned protection factors (APF) for individual items of equipment (such as assigned protection factors for respiratory protective equipment).
A SWPF needs the duration of the test and activities carried out as test exercises to be sufficiently close to operational use to be considered as representative of the performance of the ensemble in a real deployment. The ensemble tests of barrier performance in this specification would form such a SWPF test.
Selection and procurement of ensembles can be a complex, time-consuming and expensive process. There are two main approaches:
- allow manufacturers/suppliers to submit suitable individual items so that potential users/procurers can assess all the combinations of these considered appropriate; and
- follow a turnkey approach where a single manufacturer/supplier (or consortium) submits a full personal protective equipment ensemble to be assessed by the user/procurer.
There may be rules or legal liability issues which affect the choice of approach. If there is a choice between the two approaches the turnkey approach is likely to be most cost-effective for a potentially complex ensemble such as for USAR Scenario 3. The turnkey approach can also have advantages when the provision of consumable items, spares, maintenance, training and product support are considered as there is one clear manufacturer/supplier responsible.
Recommendations
The Health and Safety Laboratory recommends that the specification in this report is used as part of the process for selection and procurement of USAR PPE for Scenario 3, high dust levels and chemical, biological and radiological materials. Where there is the need for input from USAR teams or others, it is recommended that a wide-ranging consultation is conducted so that the best information can be gathered on the relative importance of aspects of ensemble performance, including more subjective characteristics like comfort and usability. It is also recommended that the assumptions on USAR operations that have been used to inform this specification are regularly reviewed.
The full report is available for download below.
