concrete roof. Roofpenetrations for vents,intakes,ovenvents,air-handling
systems and some utilities must be sealed to prevent water leakage and
subsequentinteriorair and surface contamination.
7.7 Loading bays
Truckdocksand doorsare for the purpose of unloading raw material supply
trucksor loading out trucks withfinishedgoodsor other items. This has to be
donewhilepreventingthe entranceof pests suchas rodents, insects and birdsas
well as dust and debris.One of the first considerationswhen designinga facility
is to attemptto place dockdoorsand other frequentlyuseddoors on the side of
the plant awayfrom the prevailing winds. Thenthe dock areasmust be
constructed to be as rodent proofas possible. The olderdocksthat are sunkenare
not recommended.No matter howgoodthe drain that is supposed to be at the
low point,it will become clogged withpacking material, debris,and dirt. Water
will collect and becomea contamination pointand an attractant for insects and
rodents. Dockdrivewaysshouldslopeawayfromthe building to providegood
drainage.
Concrete truck dockwalls are easilyscaleable by rodents. A simple,inexpen-
sivepreventionis to installan 18 inch(0.5 m) widestripof a verysmooth
material suchas stainlesssteelunderthe dock wall overhang. The rodents cannot
get a foothold and will be unableto climb the wall to gain access to the facility.If
the dockhas a docklevelermechanism and a restraininghook to holdthe trailer
fromrollingduringthe unloadinga rodentcan easilyjumpto the restraining
hook,climb up into the dockleveler pit and up throughthe openingbetween the
plateand the warehouse floor.An inexpensiveway to prevent this is to line the
dockleveler platewith nylonbrushes. Rodentsare reluctantto passor chew
throughthe brushes so theyprovidean effectivebarrier to rodententry.
Somefacilities evenline the bottomand sidesof the overhead truckdoors
withthesebrushesto preventrodent entrythroughgapsin the door.Ratsrequire
0.5 inches(13 mm)of spaceto gainentryinto a facility whilemice requireonly
0.25inches(6 mm).Most modern truck docksuse dockseals.Theseseals
effectively stop the entryof insects and rodents whenthe dockdooris openand
a traileris backed againstthe seal.Somedockshavea verticallift dockplate.
Whenthe dooris openedthe dockplateis loweredinto placeon the truck bed.
Whenfinished the dockplateis raised,the truck departsand the doorclosed.
Thereis no emptyspacebelowthe plateleadingto the outside,whicheffectively
shutsoff the access for rodentsand insects. The otherconcernof truck docksis
the presenceof an overhangor canopy. Manyoverhangsare constructed with
bracesand supports that are conducive to bird roostingand nesting. If overhangs
are installed theyshould be designedto be completelysmoothunderneathto
preventbirdsfromfindinga finda perchor a placeto builda nest.Older
facilities sometimes install mesh nettingunderthe dockcanopies of overhangs
to preventbirdsfromgainingaccessto possiblenesting areas.Cautionmustbe
Improvingbuildingdesign 131