# Commission Delegated Regulation (EU) 2017/654 of 19 December 2016 supplementing Regulation (EU) 2016/1628 of the European Parliament and of the Council with regard to technical and general requirements relating to emission limits and type-approval for internal combustion engines for non-road mobile machinery, Division 9.3.4.4: Verification of ambient conditions

Extent: E+W+S+N.I.

When using measurement instruments that meet the specifications in point 9.4 the following ambient conditions shall be verified:
(a) Dew point and ambient temperature shall be recorded. These values shall be used to determine if the stabilization and weighing environments have remained within the tolerances specified in point 9.3.4.3 for at least 60 min before weighing filters;
(b) Atmospheric pressure shall be continuously recorded within the weighing environment. An acceptable alternative is to use a barometer that measures atmospheric pressure outside the weighing environment, as long as it can be ensured that the atmospheric pressure at the balance is always at the balance within ± 100 Pa of the shared atmospheric pressure. A means to record the most recent atmospheric pressure shall be provided when each PM sample is weighed. This value shall be used to calculate the PM sample filter buoyancy correction in point 8.1.13.2.

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Source: https://www.legislation.gov.uk/eur/2017/654/annex/VI/division/9/division/9.3/division/9.3.4/division/9.3.4.4 (the official version)
Page: https://openlegislation.uk/eu-regulation-2017-654/annex-VI/division-9/division-9.3/division-9.3.4/division-9.3.4.4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.