1. LA AUTONOMÍA DEL PACIENTE
1.4. Derechos de libertad:
1.4.1. La intimidad y la libertad:
The higher the friction coefficient, the better friction forces contribute to the securing. The IMO Guidelines is based static friction in the calculations for top-over lashing, and the standard EN12195-1 is based only on dynamic friction. The dynamic friction is considered as 70% of the static friction. The static and dynamic frictions between various materials are shown in the tables below.
The best option to determine the actual friction between vehicle and load is to measure it. The values in the following table may be considered as a rule of thumb if such measurement is not possible. These values will also be only applicable, if the load platform is in good condition, clean and dry.
8.2.1. Static friction table
MATERIAL COMBINATION IN THE CONTACT AREA FRICTION COEFFICIENT Static
SAWN TIMBER/WOODEN PALLET
Sawn timber against plywood/plyfa/wood 0.5 Sawn timber against grooved aluminium 0.4
Sawn timber against steel 0.4
Sawn timber against shrink film 0.3
SHRINK FILM
Shrink film against plyfa 0.3 Shrink film against grooved aluminium 0.3
Shrink film against steel 0.3
Shrink film against shrink film 0.3
CARDBOARD (untreated)
Cardboard against cardboard 0.5 Cardboard against wooden pallet 0.5
BIG BAG
Big bag against wooden pallet 0.4
STEEL AND SHEET METAL
Flat steel against wooden bolt 0.5 Unpainted rough sheet metal against
wooden bolt 0.5
Painted rough sheet metal against wooden
bolt 0.5
Unpainted rough sheet metal against
unpainted rough metal sheet 0.4 Painted rough metal sheet against painted
rough metal sheet 0.3
Painted metal barrel against painted metal
8.2.2. Dynamic friction table
Dynamic friction factors of some usual goods D
Combination of materials in the contact surface Friction factor
D
Sawn wood
Sawn wood against wood 0,35
Sawn wood against grooved aluminium 0,3
Sawn wood against steel sheets 0,3
Sawn wood against crimped foils 0,2
Crimped foils
Crimped foils against fabric base laminate/plywood 0,3
Crimped foils against grooved aluminium 0,3
Crimped foils against steel sheets 0,3
Crimped foils against crimped foils 0,3
Cardboard boxes
Cardboard box against cardboard box 0,35
Cardboard box against wood pallet 0,35
Large bags
Large bags against wood pallet 0,3
Steel and metal sheets
Oiled metal sheets against oiled metal sheets 0,1
Flat steel bars against sawn wood 0,35
Unpainted rough steel sheets against sawn wood 0,35 Painted rough steel sheets against sawn wood 0,35 Unpainted rough steel sheets against unpainted rough
steel sheets 0,3
Painted rough steel sheets against painted rough steel
sheets 0,2
Painted steel barrel against painted steel barrel 0,15
Concrete
Wall on wall without intermediate layer
(concrete/concrete) 0,5
Finished part with wooden intermediate layer on wood
Combination of materials in the contact surface Friction factor
D Ceiling on ceiling without intermediate layer
(concrete/lattice girder) 0,6
Steel frame with wooden intermediate layer (steel/wood) 0,4 Ceiling on steel frame with wooden intermediate layer
(concrete/wood/steel) 0,45
Pallets
Resin bonded plywood, smooth – Europallet (wood) 0,2 Resin bonded plywood, smooth – box pallet (steel) 0,25 Resin bonded plywood, smooth – plastic pallet (PP) 0,2 Resin bonded plywood, smooth – wooden pressboard
pallets 0,15
Resin bonded plywood, sieve structure – Europallet
(wood) 0,25
Resin bonded plywood, sieve structure – box pallet (steel) 0,25 Resin bonded plywood, sieve structure – plastic pallet (PP) 0,25 Resin bonded plywood, sieve structure – wooden
pressboard pallets 0,2
Aluminium beams in the load-carrying platform (punched
bars) – Europallet (wood) 0,25
Aluminium beams in the load-carrying platform (punched
bars) – box pallet (steel) 0,35
Aluminium beams in the load-carrying platform (punched
bars) – plastic pallet (PP) 0,25
Aluminium beams in the load-carrying platform (punched
bars) – wooden pressboard pallets 0,2
If the friction is unknown, a simple method to determine the value is to
successively increase the inclination of the load platform until the object starts to
slide.
Expressed in simple terms, the coefficient of friction states how easily a cargo
unit will slide when the load platform is tilted. The friction is proportional to the
weight of the goods. The figures below illustrate some of the more common
connections between coefficient of friction and angle of inclination. A simple
method to find which measure of friction applies is to incline a load platform
with the cargo in question and measure the angle at which the cargo starts to
slide. This gives the static rest friction.
L = 200
cm
h
when the friction coefficient is
the cargo starts to slide at an angle of
equal to the heights h (cm) (if L = 200 cm)
0.2 11.3 39
0.3 16.7 57
0.4 21.8 74
0.5 26.6 89
If the friction is known it can in a similar way be checked if the cargo securing arrangement is sufficient. The load platform shall be tilted to a certain angle according to the diagram below. If the cargo stays in position, the securing arrangement is able to withstand the relevant acceleration.
0 10 20 30 40 50 60 70 80 90 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1 -factor A ngl e of i nc li na ti on Forward Sideways, backward -factor In c lin a ti o n
-factor = base divided by height (B/H)
The -factor is the lowest value of the coefficient of friction () and the ratio of breadth (B) and height (H) and number of rows (n), n H
B
, at accelerations sideways. At accelerations
forward or backward it is the lowest value of the ratio of length (L) and height (H), H
L
, and the coefficient of friction ().
For securing arrangements not allowing sliding of the cargo the static coefficient of friction is used else the dynamic friction. If the dynamic friction is unknown it is to be taken as 70% of the static friction.
The efficiency of the securing arrangement of a heat exchanger is tested for accelerations forward and sideways.