ISO 19711-2:2023

INTERNATIONAL ISO
STANDARD 19711-2
First edition
2023-10
Building construction machinery and
equipment — Truck mixers —
Part 2:
Safety requirements
Reference number
© ISO 2023
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ii
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Safety requirements and/or protective measures . 4
4.1 General requirements . 4
4.1.1 General . 4
4.1.2 Mechanical hazards . 4
4.1.3 Electrical hazards. 5
4.1.4 Thermal hazards . 5
4.1.5 Noise . 5
4.1.6 Electromagnetic compatibility (EMC) . 6
4.2 Control system . 6
4.2.1 Stop system . 6
4.2.2 Multiple control stations . 6
4.2.3 Cable-less remote control . 7
4.3 Manual control devices for emergency operation . 7
4.4 Positioning of control devices . 7
4.4.1 Control devices at the work station . 7
4.4.2 Other control devices . 7
4.5 Working lights . 7
4.6 Additional removable equipment . 7
4.7 Interface mixer device and truck or trailer . 7
4.8 Drum . 8
4.8.1 Drum access hole. 8
4.8.2 Drum-locking device . 8
4.8.3 Drum opening . 8
4.9 Flip-over chute . 9
4.10 Swivel chute . 9
4.11 Drum closure system . 9
4.12 Power transmission from the power source to the drum drive system . 9
4.13 Water system . 9
4.14 Exhaust system of the auxiliary engine . 10
4.15 Working platform at the charge device . 10
4.16 Tread at rear underrun protective device of the rear discharge type truck mixer . 10
4.17 Visual aid . 10
5 Verification of safety requirements and/or protective measures .11
6 Information for use .12
6.1 General .12
6.2 Instruction handbook.12
6.2.1 General .12
6.2.2 Noise . 13
6.2.3 Operation . 14
6.2.4 Maintenance and repair .15
6.3 Information and warnings . 16
6.3.1 Labelling for the control device . 16
6.3.2 Warnings . 16
6.4 Marking . 16
Annex A (informative) Figures .17
Annex B (normative) Noise-test code for truck mixers .30
iii
Annex C (informative) Example of a noise emission declaration .33
Annex D (informative) List of significant hazards .34
Bibliography .37
iv
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
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expressions related to conformity assessment, as well as information about ISO's adherence to
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www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 195, Building construction machinery and
equipment, Subcommittee SC 1, Machinery and equipment for concrete work.
A list of all parts in the ISO 19711 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
Introduction
This document is a type-C standard as stated in ISO 12100.
This document is of relevance, in particular, for the following stakeholder groups representing the
market players with regard to machinery safety:
— machine manufacturers (small, medium and large enterprises);
— health and safety bodies (regulators, accident prevention organizations, market surveillance, etc.).
Others can be affected by the level of machinery safety achieved with the means of the document by the
above-mentioned stakeholder groups:
— machine users/employers (small, medium and large enterprises);
— machine users/employees (e.g. trade unions, organizations for people with special needs);
— service providers, e.g. for maintenance (small, medium and large enterprises);
— consumers (in case of machinery intended for use by consumers).
The above-mentioned stakeholder groups have been given the possibility to participate at the drafting
process of this document.
The machinery concerned and the extent to which hazards, hazardous situations or hazardous events
are covered are indicated in the scope of this document.
When requirements of this type-C standard are different from those which are stated in type-A or
type-B standards, the requirements of this type-C standard take precedence over the requirements of
the other standards for machines that have been designed and built according to the requirements of
this type-C standard.
vi
INTERNATIONAL STANDARD ISO 19711-2:2023(E)
Building construction machinery and equipment — Truck
mixers —
Part 2:
Safety requirements
1 Scope
This document specifies the safety requirements for truck mixers defined in ISO19711-1.
This document does not deal with carrier vehicles, e.g. trucks, tractors, construction machinery and
mobile industrial handling equipment or other self-propelled vehicles.
This document does not include requirements which are covered in directives related to the
construction of vehicles or national road regulations.
NOTE The use in public road traffic is governed by the national regulations.
This document deals with all significant hazards, hazardous situations and events relevant to truck
mixers when they are used as intended and under the conditions of misuse which are reasonably
foreseeable by the manufacturer (see Annex D). This document specifies the appropriate technical
measures to eliminate or reduce risks arising from the significant hazards during transportation,
assembly, dismantling, disabling, scrapping, operation and maintenance of the truck mixer.
Figures to show examples in this document are listed in Annex A.
This document is not applicable to truck mixers manufactured before the date of its publication.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 19711-1, Building construction machinery and equipment — Truck mixers — Part 1: Terminology and
commercial specifications
IEC 60204-1:2016, Safety of machinery — Electrical equipment of machines — Part 1: General requirements
IEC 61000-6-2, Electromagnetic compatibility (EMC) — Part 6-2: Generic standards — Immunity standard
for industrial environments
ISO 2867, Earth-moving machinery — Access systems
ISO 3457, Earth-moving machinery — Guards — Definitions and requirements
ISO 3744, Acoustics — Determination of sound power levels and sound energy levels of noise sources using
sound pressure — Engineering methods for an essentially free field over a reflecting plane
ISO 4413, Hydraulic fluid power — General rules and safety requirements for systems and their components
ISO 4414, Pneumatic fluid power — General rules and safety requirements for systems and their components
ISO 4871:1996, Acoustics — Declaration and verification of noise emission values of machinery and
equipment
ISO 11201, Acoustics — Noise emitted by machinery and equipment — Determination of emission sound
pressure levels at a work station and at other specified positions in an essentially free field over a reflecting
plane with negligible environmental corrections
ISO 12100:2010, Safety of machinery — General principles for design — Risk assessment and risk reduction
ISO 13766-1, Earth-moving and building construction machinery — Electromagnetic compatibility (EMC)
of machines with internal electrical power supply — Part 1: General EMC requirements under typical
electromagnetic environmental conditions
ISO 13766-2, Earth-moving and building construction machinery — Electromagnetic compatibility (EMC)
of machines with internal electrical power supply — Part 2: Additional EMC requirements for functional
safety
ISO 13849-1, Safety of machinery — Safety-related parts of control systems — Part 1: General principles
for design
ISO 13850, Safety of machinery — Emergency stop function — Principles for design
ISO 13857:2019, Safety of machinery — Safety distances to prevent hazard zones being reached by upper
and lower limbs
ISO 14120, Safety of machinery — Guards — General requirements for the design and construction of fixed
and movable guards
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 19711-1, ISO 12100 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
drum opening
opening for charging and discharging the drum
3.2
control station
unit with control devices for operating the functions of the truck mixer
Note 1 to entry: The control station can be a remote-control station with cable or cable-less.
Note 2 to entry: See Figure A.1.
Note 3 to entry: Functions of the truck mixer include, e.g. rotation direction of drum, rotating speed, stop function
of the drum, working light switch, power chute switch.
3.3
work station
place where the main control station of the drum drive is arranged, that is usually located near the
discharge chute
Note 1 to entry: The work station is for operating the charging, mixing and discharging. The operator (3.8) is
either standing on ground level (see Figure A.1) or in case of rear discharge type truck mixer, it can be on the
tread at the rear underrun protective device. Additional control stations can be provided, e.g. in the cabin of the
truck.
3.4
drum closure system
device to cover the drum opening (3.1) partly or completely to prevent spilling of mixture
Note 1 to entry: The drum closure system is optional.
3.5
supporting arm
superstructure for carrying the charge device and discharge device and the working platform
3.6
rear splash guard
device below the drum preventing the drum from getting dirty
Note 1 to entry: The rear splash guard is provided on the rear discharge type truck mixer.
Note 2 to entry: See Figure A.15.
3.7
interface
connections that allow the transfer of physical forces, energies, commands and/or information (e.g.
mechanical, hydraulic, pneumatic, electrical, electronical) between the mixer device and the truck or
trailer on which it is mounted
3.8
operator
person authorised and trained to operate a truck mixer
Note 1 to entry: In general, the mixer operator is also the driver of the truck mixer.
3.9
normal operation
operation of the machine with all systems in function
3.10
emergency operation
operation of the machine with a system failure
EXAMPLE In case of energy source(s) or control system failure, a separate hydraulic power pack is
connected; and the mixer device is operated by manual valve actuation under circumvention of the emergency-
stop system.
3.11
visual aid
system that provides visual information without warning
Note 1 to entry: The system generally includes a monitor and camera.
3.12
visibility test rectangle
VTR
rectangle located on the plane ground as reference, aligned symmetrically to the longitudinal axis of
the truck mixer in order to test the visual aid (3.11)
Note 1 to entry: See Figure A.16.
3.13
truck mixer drum cleaning system
separate machine to remove residual mixture from the inside of the drum
4 Safety requirements and/or protective measures
4.1 General requirements
4.1.1 General
Machinery shall conform to the safety requirements and/or protective measures of this clause.
In addition, the machine shall be designed in accordance with the principles of ISO 12100 for hazards
that are relevant, but not significant, and which are not dealt with by this document (e.g. sharp edges).
4.1.2 Mechanical hazards
4.1.2.1 Risk of slipping
The surface of means of access, e.g. steps, working platform, shall be slip-resistant. See ISO 2867:2011,
Annex A, for examples of slip-resistant surfaces.
4.1.2.2 Risk of entanglement, crushing, shearing
To protect the operator from the risk of entanglement, crushing and shearing, fixed guards shall be
provided in accordance with ISO 14120. Due to functional restrictions, the following exceptions to
ISO 13857:2019, Table 3 and Table 4, shall apply.
For the empty truck mixer standing on level ground, Table 1 provides the minimum clearances between
the drum and non-moving parts, with the hazard zone situated at a distance W from an imaginary
vertical plane parallel to the longitudinal axis of the vehicle intersecting the most outer point of the
vehicle (reference plane).
Table 1 — Minimum clearance a depending on the distance W to the reference plane
W Minimum clearance, a
≥ 800 mm ≥ 20 mm
< 800 mm ≥ 50 mm
NOTE See Figure A.3.
Besides the general minimum clearances of Table 1, further exceptions are provided in Table 2.
Table 2 — Clearances for specific entanglement points
Entanglement points Clearance
drum roller cover - drum track
1 max. 10 mm (Figure A.6)
ring
2 drum - supporting arm min. 20 mm (Figure A.7)
3 drum - charge device bracket min. 20 mm (Figure A.8)
4 drum - discharge hopper min. 20 mm (Figure A.9)
drum - guard rail at working
5 min. 50 mm (Figure A.10)
platform
drum closure system - dis-
6 min. 20 mm (Figure A.11)
charge hopper
7 drum - extension chute min. 20 mm (Figure A.12)
drum - extension chute with
8 min. 20 mm (Figure A.13)
bracket
9 drum - concrete delivery pipe min. 20 mm (Figure A.14)
TTabablele 2 2 ((ccoonnttiinnueuedd))
Entanglement points Clearance
10 drum - rear splash guard min. 20 mm (Figure A.15)
The hazard zones shall be indicated by decals; and the residual risk shall be described (see 6.3.2).
4.1.2.3 Risk of impact, risk of injection
The hydraulic system shall be designed in accordance with ISO 4413.
The pneumatic system shall be designed in accordance with ISO 4414.
NOTE The hydraulic system and the pneumatic system of the truck or trailer are not covered.
The interface specified by the truck or trailer manufacturer shall be used.
4.1.3 Electrical hazards
Electrical installations shall conform to IEC 60204-1.
The interface specified by the truck or trailer manufacturer shall be used.
4.1.4 Thermal hazards
Parts or surfaces that reach temperatures >75 °C under normal operating conditions shall be designed,
constructed, positioned, or provided with a thermal guard to minimize the risk of contact from the
workstation in accordance with ISO 3457.
For ergonomic data that can be used to establish temperature limit values for hot surfaces, see
ISO 13732-1.
4.1.5 Noise
4.1.5.1 Noise reduction at the design stage
Machinery shall be designed and constructed in such a way that risks resulting from the emission of
airborne noise are reduced to the lowest level, taking account of technical progress and the availability
of means of reducing noise, in particular at source.
When designing machinery, the available information and the technical measures to reduce noise at the
source given in ISO/TR 11688-1 should be taken in to account.
NOTE ISO/TR 11688-2 gives useful information on noise-generation mechanisms in machinery.
Noise sources mainly include the power source(s), drum drive and the drum with its content. The power
source on the truck is the main source of noise.
In case the truck is purchased by the truck mixer manufacturer, the truck mixer manufacturer is
recommended to ask for a low-noise truck.
Noise reduction is possible, e.g. with the choice of low-noise hydraulic components, gears, auxiliary
engine if any, reduction of vibration transmitted from drive to other parts of construction and design of
the construction that prevents the arising of resonance.
NOTE See also Annex B.
4.1.5.2 Information on noise emission
Information on noise emission shall be given in the information for use (see 6.3.2).
4.1.6 Electromagnetic compatibility (EMC)
Truck mixers with combustion engine shall conform to the requirements of electromagnetic
compatibility as specified in ISO 13766-1 and ISO 13766-2.
Electric grid-connected truck mixers shall conform to IEC 61000-6-2.
Any other drive design or combination of drive designs shall conform to the applicable standards.
4.2 Control system
4.2.1 Stop system
4.2.1.1 Emergency stop
The machine shall have an emergency stop at each control station (see also 4.2.3). The emergency stop
shall conform to ISO 13850 and shall stop all power-driven machine functions.
NOTE According to the state of the art, the energy source(s), for example, the engine of the truck, auxiliary
motor, can stay in operation.
Stop category 0 in accordance with IEC 60204-1:2016, 9.2.2, shall be fulfilled.
The emergency-stop system shall fulfil performance level c in accordance with ISO 13849-1.
4.2.1.2 Normal stop
A normal stop device shall be provided to bring the machine to a complete stop. In case of a combustion
engine, the ignition lock (key- and keyless-systems) shall be considered as a normal stop device. In case
of an electric drive, an additional supply disconnecting device in accordance with IEC 60204-1:2016,
5.3 and 9.2.5.3, shall be provided. Stop category 0 in accordance with IEC 60204-1:2016, 9.2.2, shall be
fulfilled.
4.2.1.3 Starting of the machinery
An intended control device for starting the operation of the machinery shall be provided.
4.2.1.4 Restarting of the machinery
When restarting the machinery after a stoppage, an unexpected start-up of hazardous functions of the
machine shall be prevented. To prevent the unexpected start-up of the truck mixer, the safety-related
part of the control system shall fulfil performance level c in accordance with ISO 13849-1.
4.2.1.5 Devices for switching off for prevention of unexpected start-up
Means to isolate machinery from energy sources shall be provided and shall be capable to be locked.
For a truck mixer, the ignition key of the truck or the ignition key of the auxiliary engine are considered
to fulfil the requirement.
4.2.2 Multiple control stations
If there is more than one control station at the machine, the respective function shall only be possible
from one control station at the same time in accordance with IEC 60204-1: 2016, 9.2.7.4.
The safety-related part of the control system shall fulfil performance level c in accordance with
ISO 13849-1.
NOTE A mechanical control system where multiple levers are connected to activate the same function at the
same time does not fulfil the requirements of 4.2.2.
4.2.3 Cable-less remote control
A cable-less remote control is considered a control station. All requirements for control systems equally
apply for cable-less remote controls, except for the emergency stop.
A cable-less remote control shall be equipped with a stop function in accordance with IEC 60204-1:2016,
9.2.7.3. The safety-related part of the stop system shall fulfil performance level c in accordance with
ISO 13849-1. In case of the presence of a cable-less remote control, the machine shall be equipped with
at least one emergency stop at the rear (see 4.2.1.2).
4.3 Manual control devices for emergency operation
Manual control devices for emergency operation, for example, to discharge the drum, shall be protected
against unintended use, for example, by a fixed guard, a distance guard or the structure of the machinery
acting as a guard. The use of these manual control devices shall be described [see 6.2.3.1 b)].
4.4 Positioning of control devices
4.4.1 Control devices at the work station
The control devices at the work station close to drum opening shall be positioned in a distance from the
ground between 800 mm and 1 800 mm.
4.4.2 Other control devices
Handling positions of other control devices and equipment used on the construction site shall be
positioned in a maximum height from the ground or from the tread on the rear underrun protective
device in accordance with Table 3.
Table 3 — Maximum height of other control devices
Frame height Maximum height of other control devices
Up to 1 000 mm 1 800 mm
Higher than 1 000 mm up to 1 100 mm 1 900 mm
Higher than 1 100 mm 2 000 mm
4.5 Working lights
For the illumination of the work station, at least one working light shall be provided with a minimum
light power of 800 lm.
4.6 Additional removable equipment
Additional, removable equipment (e.g. extension chutes) and tools to be handled manually by the
operator shall have a maximum mass of 25 kg each. Means shall be provided for the operator to fix such
equipment and to secure it against unintended movement.
4.7 Interface mixer device and truck or trailer
The interface between the mixer device and the truck or trailer shall be designed and constructed in
accordance with the specifications defined by the truck or trailer manufacturer.
4.8 Drum
4.8.1 Drum access hole
At least one drum access hole shall be provided. The size of a drum access hole shall have a minimum
clear diameter of 500 mm except in the following cases. The mass of a drum access hole cover shall not
exceed 25 kg (see ISO 2867:2011, 5.11).
For a drum of a smaller size with a rated drum capacity up to 6 m , it shall have a minimum diameter of
420 mm. For a drum of a larger size with a rated drum capacity 6 m and over, a minimum diameter of
500 mm shall apply.
If the rectangular or oval shape is used for the opening, the larger opening dimension shall be at a
minimum 500 mm; and the smaller opening dimension shall be at a minimum 400 mm.
4.8.2 Drum-locking device
To prevent unintended rotation of the drum while the operator is working in the drum, the truck
mixer shall be equipped with a drum-locking device; alternatively, it may be purchased from the mixer
manufacturer as required under the following condition b).
It shall fulfil the following requirements.
a) The drum-locking device shall withstand a turning moment of the drum of 25 000 Nm or a force
which is created from 1 m of cured concrete within the drum.
b) The drum-locking device shall be permanently mechanically connected/linked to the machine near
the locking point. If work inside the drum is only allowed at a service shop, the drum-locking device
shall be stored where maintenance and repair work of the drum is to be conducted.
c) If intended to be handled manually (hand-held) by the operator, the weight of each single piece of
the drum-locking device shall not exceed 10 kg.
d) The drum-locking device shall be designed to work throughout the whole lifetime of the truck
mixer.
e) If a friction-based locking device is provided, it shall be designed taking into consideration that the
machine can be exposed to friction-reducing agents.
For ergonomic positioning during works inside the drum, a minimum of two locking positions shall be
provided to avoid overhead works (e.g. removal of hardened concrete or replacement of drum fins).
When the drum is locked by the drum-locking device, the drum access hole shall be located at an angle
of approximately 60° compared to the vertical plane (see Figure A.4) so that the drum can be entered
from the left and the right side of the truck.
4.8.3 Drum opening
4.8.3.1 Fixed guard at drum opening
The following access to the shearing points shall be prevented by a fixed guard:
a) drum opening to discharge hopper;
b) drum opening to charge device.
This fixed guard shall secure the area between the charge device, the drum and the discharge hopper
on the side of the working platform up to the vertical plane through the middle axis of the drum.
In addition, this fixed guard shall be shaped and located in a way that the distance between the rear
end of this fixed guard and the rear end of the drum is greater than 350 mm. The distance from the rear
end of the drum to the front end of this fixed guard shall be at least 120 mm (see also Figure A.5).
This applies to rear discharge type truck mixer. For front discharge type truck mixer, “rear end of the
guard” and “rear end of drum” should read as “front end”, also “front end of guard” should be read as
“rear end” to be opposite for each.
This fixed guard shall be in accordance with 4.1.2.2. The dimension of the openings of this fixed
guard shall be in accordance with Table 2. As an exception, for cleaning purposes, e shall be a value of
≤ 60 mm with at the same time a distance of s ≥ 120 mm to the hazard zone (rear end of drum) (see also
r
Figure A.5).
A warning sign indicating the remaining risks of crushing/shearing shall be applied close to or on this
fixed guard (see 6.3.2).
4.8.3.2 Use of truck mixer drum cleaning system
For truck mixers without drum closure systems, the charge device and, where relevant, the surrounding
structure shall be designed to be lifted or removed in order to allow access for a truck mixer drum
cleaning system.
4.9 Flip-over chute
The flip-over chute is operated manually. Therefore, it shall be equipped with at least one handle to flip
over the chute (see Figure A.17).
The flip-over chute shall be designed in a way that two-hand operation is enforced before reaching the
lowered end-position in order to reduce the risk of crushing (see Figures A.18, A.19 and A.20).
4.10 Swivel chute
Swivel chutes can be operated manually or power-driven. In case of power-driven swivel chutes, the
safety-related part of the control system shall be operated with hold-to-run devices which shall fulfil
performance level c in accordance with ISO 13849-1.
Appropriate means to fix the swivel chute in a travel position shall be provided.
4.11 Drum closure system
For power-driven drum closure systems, the crushing/shearing point shall be protected by a distance
in accordance with 4.1.2.2; alternatively, the control device shall be hold-to-run and the safety-related
parts of the control system shall fulfil performance level c in accordance with ISO 13849-1.
4.12 Power transmission from the power source to the drum drive system
Entanglement points of power-driven parts shall be covered by fixed guards in accordance with 4.1.2.2.
For the transmission shaft between the truck engine and the hydraulic pump, this requirement applies
to the top and both sides of the shaft.
4.13 Water system
If the truck mixer is equipped with a water system, cleaning equipment (e.g. hose, nozzle) shall be
provided at the work station and at the working platform.
NOTE If cleaning is not necessary at the working platform (e.g. external cleaning system), it can be provided
at the work station only.
4.14 Exhaust system of the auxiliary engine
Exhaust-gas outlets shall be arranged in such a way that during operation the gases are not directed to
the work station area.
4.15 Working platform at the charge device
A working platform to be accessed via a ladder in vicinity to the device shall be provided, conforming
to the requirements of ISO 2867. A working platform is not required if routine tasks in this area can be
performed remotely, or if other means of access is provided.
Further, the following apply.
a) The minimum dimensions of the working platform shall be 400 mm × 600 mm.
b) The ladder beams may be considered as handrails.
c) The maximum distance between the first step of the ladder and the ground shall be 500 mm.
In addition to the requirements for guard rails in accordance with ISO 2867, the guard rail of the
working platform shall be designed in order to prevent operators from standing on an intermediate
level (height) between the foot barrier and the handrail (an example is shown in Figure A.2). This
applies to the guard rail on the left, right and rear side of the working platform in driving direction (as
shown in Figure A.2).
A self-closing barrier shall be provided. The barrier shall have at least a handrail positioned at the same
level as that of the guard-rail that it extends to.
The barrier shall be designed to open onto the working platform and to close against a firm stop to
prevent operators from pushing against it and falling through the opening. Barriers shall be subject
to the same loading criteria as guard-rails. The maximum opening left by the closed barrier shall not
exceed 120 mm.
NOTE The working platform is not considered as a work station.
4.16 Tread at rear underrun protective device of the rear discharge type truck mixer
The crossbar of the rear underrun protective device shall be equipped with a tread. In case it cannot be
equipped on the crossbar due to design reason, a separate tread shall be provided on the other place (e.g.
behind the crossbar). In addition, a step is not necessary for a small truck mixer, therefore this subclause
does not apply. By exception to ISO 2867, the minimum size of the tread shall be 400 mm × 160 mm. The
longer side of the tread shall be parallel to the longitudinal axis of the crossbar.
Its surface shall be designed to be slip-resistant and shall be horizontal when the rear underrun
protective device is in its driving position. The upper edge of the tread shall be at the same height or at
a maximum 10 mm lower than the upper edge of the crossbar of the rear underrun protective device.
The ladder and/or the structure of the machine may be considered as handrail/handles.
In relation to the longitudinal axis of the truck mixer, the tread shall be positioned at the same side as
the work station. In relation to the longitudinal axis of the crossbar, it shall be directed towards the
work station.
If the rear underrun protective device is of a flip-over type, appropriate means to fix it in the flip-over
position shall be provided.
4.17 Visual aid
A visual aid shall be provided as additional means of hazard detection when moving or repositioning
the machine (e.g. mirror, camera/radar and monitor).
The visual aid shall survey the rear section and shall be activated when engaging the reverse gear of
the truck or additionally by manual action. The visual aid shall cover the area of the VTR.
The minimum dimensions of the VTR are width c = 3 500 mm and length a = 5 000 mm. The VTR starts
at the rear underrun protective device in its driving position (see Figure A.16).
The test object, a cube with an edge length of 200 mm, shall be completely visible in the VTR, with
the exception of the masked area due to the discharge components and the rear underrun protective
device.
5 Verification of safety requirements and/or protective measures
Safety requirements and/or measures of Clause 4 shall be verified as specified in Table 4.
The following methods of verification are considered in Table 4:
a) visual check: verification, by visual inspection, of the integrity of the machine, system or component
(e.g. guards, visual warning devices and labels, plates) and documents and drawings provided in
accordance with this document;
b) functional test: verification, by means of a no-load test, that, under no-load operating conditions,
the normal cycle, or part of the cycle, the machine with all of its safety devices functions as required
and all functions fulfil the requirements of this document and technical documentation;
c) measurement/calculation: verification that the measurable parameters established conform to
the requirements of this document (e.g. geometric dimensioning, safety distances, insulation
resistance of electric circuits, noise, vibration).
Table 4 — Verification of the safety requirements
Method of verification
Subclause Safety requirement and/or protective
Visual Functional Measure- Calcu-
in Clause 4 measure
check test ment la-tion
4.1.2.1 Requirements to avoid slipping X
Requirements to avoid entanglement,
4.1.2.2 X X
crushing, shearing
Requirements to avoid impact, risk of
4.1.2.3 X X
injection
4.1.3 Electrical installation X X X X
4.1.4 Thermal guarding X X
4.1.5 Noise X
4.1.6 Electromagnetic compatibility X
Normal stop, supply disconnecting
4.2.1.1 X X
device
4.2.1.2 Emergency-stop device X X X
Requirements to avoid unexpected start-
4.2.1.3 X X X
up of the machinery
Devices for switching off for prevention
4.2.1.4 X X
of unexpected start-up
Requirements for multiple control sta-
4.2.2 X X X
tions
4.2.3 Cable-less remote control X X
Manual control devices for emergency
4.3 X X X
operation
4.4 Positioning of control devices X X X
TTabablele 4 4 ((ccoonnttiinnueuedd))
Method of verification
Subclause Safety requirement and/or protective
Visual Functional Measure- Calcu-
in Clause 4 measure
check test ment la-tion
4.5 Working lights X X X
Requirements for additional, removable
4.6 X X X
equipment
Requirements for interface between
4.7  X
mixer and truck or trailer
...