BS ISO 16900-12:2016 pdf download

BS ISO 16900-12:2016 pdf download.Respiratory protective devices — Methods of test and test equipment — Part 12: Determination of volume-averaged work of breathing and peak respiratory pressures
1 Scope
This part of ISO 16900 specifies the test methods for determining the volume-averaged work of breathing and peak respiratory pressures imposed by the respiratory protective device (RPD).Elastic work, elastic physiological effects, and information on physiological effects of work of breathing (WOB) are specified in ISO 16976-4 and are not included in this test method.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 16972, Respiratory protective devices — Terms, definitions, graphical symbols and units of measurement
ISO 16900-5, 1) Respiratory protective devices — Methods of test and test equipment — Part 5: Breathing machine, metabolic simulator, RPD headforms and torso, tools and verification tools
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16972 and the following apply.
3.1 breathing frequency
number of breaths taken in a minute
Note 1 to entry: Expressed in breaths per minute.
3.2 elastance
E
pressure change resulting from a volume change
Note 1 to entry: Expressed in kPa/l.
3.3 tidal volume
V T
size of a breath
Note 1 to entry: Expressed in litres.
5 General test requirements
Unless otherwise specified, the values stated in this part of ISO 16900 are expressed as nominal values. Except for temperature limits, values which are not stated as maxima or minima shall be subject to a tolerance of ±5 %. Unless otherwise specified, the ambient temperature for testing shall be between 16 °C and 32 °C and (50 ± 30) % RH. Any temperature limits specified shall be subject to an accuracy of ±1 °C. Where the assessment of the pass/fail criterion depends on a measurement, an uncertainty of measurement as specified in Annex A shall be reported.
6 Principle
The RPD is fitted to a headform/torso and is operated at the manufacturer’s minimum condition, unless specified otherwise by the performance standards. The breathing machine or metabolic simulator, as applicable, is operated at a combination of tidal volume and breathing frequency, in accordance with the relevant performance standard. The work of breathing is calculated from recorded measurements of volume and pressure. These recordings will also provide peak pressures values. Validation of work of breathing measurements and calculations is performed using the verification orifices as specified in ISO 16900-5. Validation of the correct functioning of the breathing machine/metabolic simulator is performed using the validation orifices specified in ISO 16900-5. Validation is satisfactory when the WOB calculations give results which are in accordance with the data shown in Table 1.