9.3 Requirementsfor flooringmaterials
9.3.1 Slipresistance
In France and the UK, withlittlevariationfromyearto year,around20%of all
workplace injuriesleadingto working dayslost are caused by falls on the same
level(slips,trips,etc.). This causeof injuriesrankssecond after accidents during
manualhandling. Theseinjuriesare also responsible for 20%of all working days
lost, 20%of accidents leadingto a permanent incapacityto workand 2% of the
fatalinjuries(Leclercq and Tissot, 2004). A highrisk of slippingexists in the
foodindustrybecause wet and/or greasy floors are frequent, especially where
meat is processed. In slaughterhouses, slipping is the cause of 16% of
occupationalaccidents.In orderto decreaseslipping accidents, anti-slipfloors
are necessary. Wearing anti-slipfootwear is alsonecessarybut not sufficient
and,as for all risksat work,collective measures againstaccidents mustalways
be takenbefore individualmeasures. Unfortunately, anti-slip properties of floors
are obtained by increasingsurfaceroughness, whilesmooth flooringmaterials,
supposed to be the more cleanableones,are therefore not appropriate. By
contrast, efficientcleaningof the floorsis necessary to decreaseboththeir
slipperiness and theirmicrobial load.
Regulation
According to the EuropeanDirective89/391/EECemployers are responsiblefor
implementinga process of prevention of accidentsand otherwork-relatedhealth
problems basedon nineprinciples.Thisprocess of preventionis basedon a
hazardassessment.Thehazards thatcannotbe avoided must be evaluated
(principle 2), and mustbe combated at source(principle 3). Collective protective
measures mustbe takenbefore individual protectivemeasures (principle 8).
Appropriate informationmust be given to employees(principle 9). For instance,
an effective cleaningprocedureto removegreasysoil and to obtainthe correct
durability of the floorsmust be knownby employees.Employeesmustalso be
instructednot to run.
Surfacetexture
Thereis a generalawareness that smoothfloorsurfaces are slippery,especially
whenwet and/or greasy,and that rougher surfacesare safer, but it is onlyin the
past two decades that scientific research has beenconductedon the impactof
roughness on underfootfriction(Changet al., 2001).Gro»nqvistet al.(1990,
1992)proposed threeroughness factorsthat seemedto determinethe anti-slip
resistance of contaminated floorsand footwear: (1) the macroscopicstructure
(e.g.profile asperities); (2) the microscopic roughness (e.g.Ra, the arithmetic
meanroughness) and (3) the microscopicporosity of the floor.Harrisand Shaw
(1988)fromthe Healthand SafetyExecutive (UK) proposedtheRz(previously
calledRTM) whichis the average of the singlepeak-to-valleyheights of five
adjoining samplinglengths.Rzcan be measuredby a portableand inexpensive
profilometer.For this reason,it is appreciatedfor measurementof roughnessin
Improving the design of floors 173