NCC 2019 Volume Two
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Part 2.5 Safe movement and access
Explanatory Information:
Explanatory Information:
Objective
O2.5
The Objective is to provide people with safe access to and within a building.
Functional statements
F2.5.1 Safety from falling
A building is to provide safe access for people to the services and facilities within.
Performance Requirements
P2.5.1 Movement to and within a building
So that people can move safely to and within a building—
(a)
walking surfaces must have safe gradients; and
(b)
any stairway or ramp must—
(i)
have suitable handrails where necessary to assist and provide stability to people using the stairway or ramp; and
(ii)
have suitable landings to avoid undue fatigue of users; and
(iii)
be suitable for safe passage in relation to the nature, volume and frequency of likely usage; and
(iv)
have slip-resistant walking surfaces on ramps, and on stairway treads or near the edge of the nosing.
P2.5.2 Fall prevention barriers
Where people could fall—
(a)
1 m or more—
(i)
from a floor or roof or through an opening (other than through an openable window) in the external wall; or
(ii)
due to a sudden change of level within or associated with a building; or
(b)
2 m or more from a floor through an openable window in a bedroom; or
(c)
4 m or more from a floor through an openable window not covered by (b),
a barrier must be provided which must be—
(d)
continuous and extend for the full extent of the hazard; and
(e)
of a height to protect people from accidentally falling from the floor or roof or through the opening or openable window; and
(f)
constructed to prevent people from falling through the barrier; and
(g)
capable of restricting the passage of children; and
(h)
of strength and rigidity to withstand—
(i)
the foreseeable impact of people; and
(ii)
where appropriate, the static pressure of people pressing against it.
Verification Methods
V2.5.1 Wire barriers
Compliance with P2.5.2(f) and (g) for wire barriers is verified when the wire barrier passes the test described below:
(a)
Application
The test must be carried out on either—
(i)
a prototype of a wire barrier that is identical to that proposed to be installed on site; or
(ii)
a wire barrier installed on site.
(b)
Test equipment
The test equipment must consist of the following:
(i)
A horizontally suspended 125 mm diameter, 405 mm long cylinder of 1 mm thick steel having a highly polished 105 mm long cone at one end with a 20 mm diameter flat leading edge to which an eye bolt is fixed.
(ii)
A sufficiently flexible horizontal cable with mechanisms capable of applying and measuring a tension of 150 N (or a 15.3 kg weight suspended over a low friction pulley) is to be attached to the eye bolt (see Figure V2.5.1).
(iii)
A mechanism capable of measuring the tension force applied to each wire.
Figure V2.5.1 Apparatus for testing wire barriers
(c)
Test procedure
The test procedure must be as follows:
(i)
Tension the wires, within their safe load, to the same tension in all wires and measure the tensions with a strain indicator.
(ii)
For—
(A)
horizontal or near horizontal wires, position the cone against a pair of wires at the mid-span between supports, then apply the 150 N tension force to the cone; and
(B)
vertical wires, position the cone against a pair of wires at the mid-span between supporting rails, then apply the 150 N tension force to the cone; and
(C)
near-vertical wires, position the cone against a pair of wires at the widest opening between the wires, then apply the 150 N tension force to the cone.
(iii)
(iv)
When the cone is just prevented from pulling through the gap, the wires are at the correct tension in which case the cone is withdrawn and the tension recorded.
(v)
(vi)
For prototype tests of horizontal or near horizontal wires, record the deflection of each wire at the average tension calculated in accordance with (v) when a 2 kg mass is hung at mid-span between supports.
(d)
Test report
The test report must include the following information:
(i)
The name and address of the person supervising the test.
(ii)
The test report number.
(iii)
The date of the test.
(iv)
The wire manufacturer's name and address, and specifications of the wires used in the test including the safe load limit of the wires.
(v)
The construction details of the test specimen, including a description and drawings and details of the components including supports, post or railing spacings and wire spacings.
(vii)
For prototype tests of horizontal or near horizontal wires, the deflection measured in accordance with (c)(vi).
Explanatory information:
Explanatory information:
V2.5.1 is a means to verify that a proposed wire barrier satisfies the requirements of P2.5.2(f) and (g).
The meaning of the phrase "prototype that is identical to that proposed to be installed" is similar to the testing of prototypes for fire resistance. That is the prototype and the installation must be identical with respect to the type of wire, the wire diameter, the number of lays, the wire tension, the post spacing and size, etc.
The test procedure is slightly different for barriers with horizontal or near horizontal wires and vertical wires or near vertical wires (see the test procedures set out in V2.5.1(c)(ii)).
V2.5.1(c)(vi) allows measuring deflection of wires to verify that the required tensionhas been achieved.
It should be noted that V2.5.1 is only one form of compliance solution which can be used to demonstrate compliance with P2.5.2(f) and (g). The following means of verification are available:
- V2.5.1.
- The Deemed-to-Satisfy Provisions in 3.9.2.5.
- A Performance Solution that uses one of the other NCC Assessment Methods which verifies that P2.5.2(f) and (g) will be achieved.
See also explanatory information to 3.9.2.5.