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WHO Technical Report Series, No. 992, Annex 5
Supplement 8
Step 4 – establish acceptance criteria: e protocol should dene the required
acceptance criteria, based on the type of TTSPPs being stored, clearly stating
the temperature limits that are allowable within the area to be mapped – for
example: + 2.0 °C to + 8.0 °C or + 15.0 °C to + 25.0 °C. However, some mapping
studies may be performed without predening any acceptance criteria. is type
of study can be used to establish the types of product that can safely be stored in
a specic space, and what remedial actions might have to be taken to improve
the thermal performance of the space in order to optimize its use.
If the temperature-mapping study is designed to include door opening(s),
this should be stated in the study methodology and acceptance criteria. Also
the door opening parameters (frequency and duration) should be dened. e
temperature should be maintained within the dened temperature limits except
for a maximum of 30 minutes following the door opening.
Step 5 – determine EDLM locations: Use the site survey to mark the required
locations of the EDLMs. A risk-based approach can be applied to dene these
locations. However, the following guidelines will help determine the number
and location of the EDLMs required.
Length and width: EDLMs should be arranged in a grid fashion along the width
and length of the area so that the area is reasonably covered, with EDLMs located
every 5–10 metres.
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e chosen sensor grid should take account of:
■ the layout of the area (e.g. whether it is square or includes alcoves);
■ the degree to which shelving and products may aect airow;
■ where products are placed. e positions of EDLMs should coincide
with locations where TTSPPs are actually stored or planned to be
stored. For example, it may be unnecessary to t EDLMs in areas
such as the upper part of high loading bays;
■ other considerations that may warrant more or fewer EDLMs.
Height: At each point on the grid, arrange EDLMs vertically as follows:
■ If the ceiling height is 3.6 metres or less, position EDLMs directly
above one another at high, medium and low level (e.g. one EDLM
at oor level, one at 1.2 metres and one EDLM at 3.0 metres.
■ If the ceiling height is greater than 3.6 metres, EDLMs can be
arranged in vertical arrays at the bottom, middle (multiple) and
top of the space. For instance, for a storage area 6 metres in height,
EDLMs can be positioned in each grid location at heights of
0.3metres, 1.8 metres, 3.6 metres and 5.4 metres.
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In very large facilities, this can be up to 20 or 30 metres.