Specifiche di progettazione e costruzione per scale alla marinara

18.05.2017 17:38

La norma di riferimento per le specifiche di progettazione e costruzione per scale alla marinara è la EN 14122-4.

Di seguito viene riportato un estratto della norma con le indicazioni specifiche per il tipo di applicazione..

 
 
5 Specific requirements of ladder systems 
 
5.1 General requirements
The ladder system shall be designed so that the ladder itself and its attachment withstand reasonably foreseeable static and dynamic conditions. Criteria to be considered are, for example, the following:
— weight of the ladder system;
— maximum number of person staying in the ladder system;
— additional action occurring when the fall arrester will be activated.
If no other action/loads are relevant the, actions in 5.1.1 to 5.1.3 shall be applied.
 
5.1.1 Permanent action (dead load)
The mass of every component of the ladder shall be taken into account.
 
5.1.2 Variable action (rated load)
Loads F1 = 1,5 kN and F2 = 1,5 kN (see Figure 6) shall be used during the design of a ladder to represent a person.
The simulated load for the rungs F1 (see Figure 6 a) and b) for a person shall be applied perpendicular to the rung at the most unfavourable position and equally distributed over a maximum length of 100 mm.
The simulated loads for the stile(s) F2 shall be applied with a separation distance of 2 000 mm and
parallel to the longitudinal axis of the ladder. The distance between the loads F2 and the stile(s) shall be 300 mm [see Figure 6 c)].
For ladders with two stiles, the load F2 shall be taken to be shared equally by both stiles [see Figure 6 c)].
For platforms and landings as specified in 5.6, a concentrated load of 1,5 kN per person, applied at the most unfavourable position, shall be taken in to account.
For platforms, intermediate landings and moveable rest landings (one part) [see Figure 21 a)],
concentrated loads are loads distributed over a load area of 200 mm x 200 mm.
For moveable rest landings (two parts) [see Figure 21 b)], concentrated loads are loads distributed over two load areas, each of 100 mm x 100 mm.
Platforms shall be designed in accordance with ISO 14122-2 and ISO 14122-3.
 
Figure 6 — Simulated loads on the ladder
 
Key
F1 simulated load for rungs 
F2 simulated load for stiles
 
5.1.3 Additional loading
5.1.3.1 General
Additional loading, e.g. caused by wind or snow, fall protection devices (see 5.1.3.2 and 5.1.3.3) shall be taken into account in stability calculations.
Loading on ladders, e.g. by impacts of trucks, is normally not considered.
 
5.1.3.3 Safety cage
For the design of the safety cage, as a minimum the test procedure of 6.2.2 shall be applied.
5.1.3.4 Ladder anchorage system
Calculations shall take into account a minimum load of >3 kN acting on each stile for ladders with two stiles, and a load of >6 kN acting on the single stile of ladders with one stile.
For calculation, it may be assumed that the load will be transmitted to fixed parts of surroundings (e.g. wall or enclosure of the machine) by four anchorage points
 
 
Figure 7 — Arrangements of anchor points and connections
 
Key
1 rung
2 stile
3 mounting
4 anchor point
5 fixed part (e.g. wall)
 

5 Specific requirements of ladder systems

 

5.1 General requirements

The ladder system shall be designed so that the ladder itself and its attachment withstand reasonably foreseeable static and dynamic conditions. Criteria to be considered are, for example, the following:

—   weight of the ladder system;

—   maximum number of person staying in the ladder system;

—   additional action occurring when the fall arrester will be activated.

If no other action/loads are relevant the, actions in 5.1.1 to 5.1.3 shall be applied.

 

5.1.1 Permanent action (dead load)

The mass of every component of the ladder shall be taken into account.

 

5.1.2 Variable action (rated load)

Loads F1 = 1,5 kN and F2 = 1,5 kN (see Figure 6) shall be used during the design of a ladder to represent a person.

The simulated load for the rungs F1 (see Figure 6 a) and b) for a person shall be applied perpendicular to the rung at the most unfavourable position and equally distributed over a maximum length of 100 mm.

The simulated loads for the stile(s) F2 shall be applied with a separation distance of 2 000 mm and
parallel to the longitudinal axis of the ladder. The distance between the loads F2 and the stile(s) shall be 300 mm [see Figure 6 c)].

For ladders with two stiles, the load F2 shall be taken to be shared equally by both stiles [see Figure 6 c)].

For platforms and landings as specified in 5.6, a concentrated load of 1,5 kN per person, applied at the most unfavourable position, shall be taken in to account.

For platforms, intermediate landings and moveable rest landings (one part) [see Figure 21 a)],
concentrated loads are loads distributed over a load area of 200 mm x 200 mm.

For moveable rest landings (two parts) [see Figure 21 b)], concentrated loads are loads distributed over two load areas, each of 100 mm x 100 mm.

Platforms shall be designed in accordance with ISO 14122-2 and ISO 14122-3.

 

Figure 6 — Simulated loads on the ladder

 

Key

F1 simulated load for rungs

F2 simulated load for stiles

 

5.1.3 Additional loading

5.1.3.1 General

Additional loading, e.g. caused by wind or snow, fall protection devices (see 5.1.3.2 and 5.1.3.3) shall be taken into account in stability calculations.

Loading on ladders, e.g. by impacts of trucks, is normally not considered.

 

5.1.3.3 Safety cage

For the design of the safety cage, as a minimum the test procedure of 6.2.2 shall be applied. (refer to fixed ladder tests)

 

5.1.3.4 Ladder anchorage system

Calculations shall take into account a minimum load of >3 kN acting on each stile for ladders with two stiles, and a load of >6 kN acting on the single stile of ladders with one stile.

For calculation, it may be assumed that the load will be transmitted to fixed parts of surroundings (e.g. wall or enclosure of the machine) by four anchorage points

 

 

Figure 7 — Arrangements of anchor points and connections

 

Key

1     rung

2     stile

3     mounting

4     anchor point

5     fixed part (e.g. wall)

 

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