It is importantto keepin mindthat edibleproducts or products that are used
in direct contactwiththe humanbodyare being processed.Designersmust put
as mucheffort into the hygienicdesignof the electricaland controlsystemsas in
the designof the electricaland control systemsthemselves.
The following issues should be borne in mind when designing and
implementinghygienicinstallations:
∑ use of correct materials;
∑ methodof construction;
∑ cleanability of installation.
All recommendationsgivenin this chapter are also generally applicablefor air,
waterand otherkindsof tubingin the field or on a machine. Withrespect to
hygiene,air tubescan, in mostcases,be treatedin a similarmanneras electrical
cabling.
15.3.2 Basicrequirements
The basicrequirementsfor hygienicdesignof installations,not in directcontact
withproduct, are as follows:
∑ The exterior or non-contactmaterial surfacesshould be arrangedto prevent
harbouring,growthand developmentof soils,microorganisms,pestsand
verminin and on the equipment itselfas wellas in contactwithother
equipment, floors,walls or hangingsupports.
∑ To designinstallationssuchthat maintenance and operating personneldo not
haveto put in unnecessary extraeffortto keepthe areahygienicbecause of
the accessinadequacies in the installation.Instead, the installationshould
providea stimulant to helpensure it is kepthygienic.
∑ In high-hygiene zonesall trunkingsand conduitsfor cabling/wiringshouldbe
closedand sealed.Theirexternal surfacesshouldbe capableof beingcleaned
easily.Installing trunkingand/or conduit in the horizontalplane withinthe
splashareaor contactareashouldbe avoided.Although the use of cable
ladder,cabletray and wiretray is widelyusedin `normal'areas, theseare not
suitablefor installation within hygienic areassincecleaningis problematic
becauseof the nature of theirconstruction and positioningof cables.
∑ In medium hygiene zonescable laddersor wire trays and conduitsfor
cabling/wiringshouldbe used.Theirexternal surfacesshould be capable of
beingcleanedeasily. Cableladders shouldbe installed verticallyto minimise
the spacetakenin the horizontal plane.Conduitsshould not be usedin dry
production areas;small wiretrayscan be usedhere.
∑ Equipment and support structures shouldbe attached to the building (floors,
walls,columns, ceiling)in sucha way that neitherpockets nor gapsexist in
whichproductor soil can accumulate or any gapsshould be large enoughto
be fully cleanable.
Improvingthe hygienicdesignof electricalequipment 243