Algorithm of conduct for the selection of safety measures for machines

In figure 1 the algorithm of conduct described below, referring to the selection of safety measures for sufficient reduction of risk connected with identified hazards for which sufficient risk reduction has not been achieved, has been presented

1. Recognition of necessary activities ensuring required risk reduction

If the risk connected with identified hazard (see T.4.2) is at a high or average level, the activities should be taken up to reach a sufficient reduction of risk (see T.4.3 p. 1).

To each of the above-mentioned hazards a procedure should be carried out for the reduction of risk according to determined order (location in the program: new machines/basic functions/selection and application of safety measures)

2. Application of intrinsically safe structural solutions

2.1 Is it possible to

· properly select geometrical features of a machine?

– shape of a machine (selection of methods of implementation):

Method of implementation	Selection (X)
limitation of invisible places
selection and location of devices for indirect viewing (e.g. mirrors)
taking into account the viewing capacity of the operator with respect to supervision of: – movement and operation of mobile machines – movement of lifted loads or loading bases of the machines for lifting people – interface of the tool with a processed material by the hand-held or manually operated machines – presence of persons in hazard zones.
enabling the maintenance of appropriate working position by the operator
enabling proper access to control elements

– shape and positioning to one another of the mechanical components of the machines (selection of methods of implementation):

Method of implementation	Selection (X)
enlarging the smallest spacings between movable parts to maintain safety if a given body part occurs in the designed spacing
reducing the spacings between movable parts so that no body part can be put there

– edges and corners of the machine available for the user (selection of methods of implementation):

Method of implementation	Selection (X)
avoiding sharp edges and corners
avoiding protruding parts
avoiding rough surfaces
avoiding protruding parts
avoiding openings constituting a hazard for body parts or clothing

· take into account physical characteristics of the operator?

– operator’s strength (selection of methods of implementation):

Method of implementation	Selection (X)
limitation of force needed to start up the machine
limitation of weight and/or speed of moving elements

– resistance of operator to machine elements impact (selection of methods of implementation):

Method of implementation	Selection (X)
limitation of weight and/or speed of moving elements

– resistance of operator to the work environment factors impact (selection of methods of implementation):

Method of implementation	Selection (X)
limiting of noise emissions at source (e.g. use of sound absorbing materials)
limiting of vibrations emissions at source (e.g. change of distribution or enlarging of weight, change of frequency and/or amplitude of machine elements movements)
limiting of emissions of noxious substances (e.g. use of less noxious substances or processes limiting dusting)
limiting of radiation emissions (e.g. elimination of hazardous radiation sources, limiting the radiation force to the lowest level enabling proper machine operation, enlarging the distance between the radiation source and operator)

· take into account the properties of the machine stemming from general technical knowledge?

– mechanical loads (selection of methods of implementation):

Method of implementation	Selection (X)
applying proper calculation methods
applying proper construction and connection methods
preventing overloading (e.g. use of fuses, pressure relief valves or torque)
avoiding wearing of the elements subject to variable loads (e.g. cyclical)
static and dynamic balancing of rotating elements application of safety coefficients for calculation of loads of machine elements (if durability of given parts or units is a critical factor with respect to safety)

– properties of materials used (selection of methods of implementation):

Method of implementation	Selection (X)
taking into account resistance to corrosion, ageing, abrasion and wear
taking into account hardness, ductility, brittleness
taking into account uniformity
taking into account toxicity and flammability

· take into account the selection of a technique for defined machine applications?

– adjusting to operation in explosive atmospheres or the ones at risk of fire (selection of methods of implementation):

Method of implementation	Selection (X)
application of fully pneumatic or hydraulic control system and drive elements
application of intrinsically safe electrical equipment
application of equipment ensuring the maintenance of temperature fairly below the ignition point

– adjusting to operation in environment in which a great exposure to noise occurs (selection of methods of implementation):

Method of implementation	Selection (X)
application of electrical equipment in place of pneumatic one
application of equipment for water cutting instead of mechanical equipment

· take into account application of the principle of mechanically forced interaction (selection of methods of implementation)?:

Method of implementation	Selection (X)
moving through a movable mechanical structural element of other structural element through direct contact or through rigid elements

· take into account the stability of machines?

– adjusting the stability of application conditions (selection of methods of implementation):

Method of implementation	Selection (X)
taking into account the shape and dimensions of the machine base
taking into account the weight distribution with load
taking into account dynamic forces generating the turning point, caused by the movements of the machine and its parts, or elements supported by it
taking into account the change of positioning of the centre of gravity
taking into account external forces (e.g. wind pressure and muscle strength)
taking into account vibrations which could be the reason for loss of stability
taking into account terrain conditions occurring during transport or placement of the machine (e.g. floor condition, inclination)

· take into account the ease of use (selection of methods of implementation)?

Method of implementation	Selection (X)
ease of access taking into account the surroundings and human body size, considering the size of workwear and used work tools
ease of movement taking into account human capabilities
limiting the number of special tools and equipment used

· take into account the principles of ergonomics?

– appropriate tasks distribution between the operator and the machine (selection of methods of implementation):

Method of implementation	Selection (X)
taking into account the automation level of the manufacturing process
taking into account the physical capabilities and working position
taking into account movement amplitude, frequency of cyclical actions
taking into account appropriate interaction of machine and operator (by using clear control, signalling and informative elements enabling full and uniform interaction between the operator and the machine

– limitation of ergonomic nuisances connected with machine use (selection of methods of implementation):

Method of implementation	Selection (X)
avoiding strenuous body positions and its movements during machine use (e.g. by adjusting the machines to different operators)
ensuring easy operation of the machines taking into account the human effort, activation of control elements and anatomical structure of human limbs
avoiding connecting the operator’s work rhythm with the automatic machine operation cycles

· take into account the protection against electrical hazards (selection of methods of implementation)?

Method of implementation	Selection (X)
observing requirements concerning the design of electrical equipment of the machines
observing the requirements of the standards referring to special machines, such as manual machines or electrically driven portable machines

· take into account the protection during the use of pneumatic and hydraulic equipment?

– increasing the operating reliability (selection of methods of implementation):

Method of implementation	Selection (X)
use of devices limiting pressure (preventing the exceeding of maximum allowable pressure)
preventing hazards resulting from the fluctuation or increase of pressure
preventing hazards resulting from the dissipation or drop of pressure, or loss of vacuum conditions
preventing hazards resulting from leakage or damage of elements (hazardous discharge of liquids or impact as a result of sudden movement of flexible hose)
fulfilment of requirements with respect to the provisions and principles concerning containers
securing the equipment elements (pipes, flexible hoses) against harmful influence of work environment
ensuring pressure discharge in the containers (automatically) or providing the machine with the measures for disconnecting, discharging and monitoring of pressure
equipping the elements remaining under pressure after the disconnection of the machine from the power supply with clearly recognisable triggering devices and warning plate (informing about the necessity to discharge pressure before conducting setup activities or activities connected with the machine exploitation)

· use intrinsically safe structural solutions in the control systems?

· reduce exposure to hazards by mechanisation or automation of transporting works?

– use of automation and mechanisation of transport processes (selection of methods of implementation):

Method of implementation	Selection (X)
use of robots
use of manipulators
use of handling equipment
use of insufflators
inspection of automatic feeding and receiving devices with own control systems that should be coupled with the machine control system taking into account the flow of all of the safety functions in all methods of control and types of operation of these devices

· take into account the location of setup and maintenance stations of the machine (selection of methods of implementation)?

Method of implementation	Selection (X)
location of setup and maintenance places of the machine outside the hazard zones

In the field “-Application of intrinsically safe structural solutions” (annex 1) a list of selected measures should appear

2.2 Whether as a result of these activities with respect to a given hazard:

Item	Question	Selection (X)
a	a hazard (which?) will be eliminated, which shall enable to avoid additional protective measures?
b	the risk connected with a given hazard shall be sufficiently limited (assessment according to D 4.2), which shall enable to avoid additional protective measures?
c	the risk connected with hazards shall not be sufficiently limited and the use of technical and/or complementary protective measures will be necessary? (Unacceptable risk)

To answer questions b and c a repeated risk assessment connected with a given hazard (according to D 4.2) needs to be performed and upon taking into consideration all of the intrinsically safe design solutions used.

If the hazard is eliminated, this should be indicated in the field “Risk evaluation result (1)” in the table in annex 1. If the risk assessment is conducted, then in the field “Risk evaluation result (1)” an answer concerning the risk level appears (according to D 4.2).

If the action does not lead to the elimination of hazard or sufficient reduction of risk (point a and b) connected with the identified hazard, then (point C) it is necessary to take up actions defined in p. 3 and in the table in the field “Risk evaluation result (1)” an answer “unacceptable risk” will appear. In the case of an answer a or b, the risk reducing activities may be deemed completed.

3. Use of technical and complementary protective measures

3.1 Is it possible to:

· adequately select and apply the guards?

· adequately select and apply the sensitive protective equipment?

· take into account the use of measures ensuring stability

– use of machine elements ensuring stability (selection of methods of implementation):

Method of implementation	Selection (X)
anchor bolts
devices determining the position
movement limiters
mechanical bumpers
acceleration and delay limiters
load limiters
devices warning against exceeding the stability limit or overturning limit

· take into account measures limiting the effects of operator’s error?

– use of devices for limiting operator’s errors (selection of methods of implementation):

Method of implementation	Selection (X)
limiting movement parameters (distance, angle, speed, acceleration)
securing against overloading of parts and units, and exceeding the torque
preventing collisions or adverse mutual interactions of machines
preventing the occurrence of hazards for pedestrian operators driving mobile machinery or other pedestrians
limiting the pressure or temperature
supervising machine emissions
preventing the machine operation when operator is absent from the control station
preventing the lifting operation when the machine stabilisers are positioned incorrectly
limiting the inclination of the machine placed on a slope
ensuring safety position of all components before starting to move the machine

· apply additional technical protective measures limiting emission?

– limiting the noise (selection of methods of implementation):

Method of implementation	Selection (X)
housings
screens installed on machines
silencers

– limiting vibrations (selection of methods of implementation):

Method of implementation	Selection (X)
vibrations isolators (e.g. devices suppressing vibrations), placed between the source and person exposed
elastic suspensions
seats with a suspension system suppressing vibrations

– limiting the emissions of noxious substances (selection of methods of implementation):

Method of implementation	Selection (X)
machine housing
local exhaust ventilation with filtering
dampening with liquids
air curtains
cabins for operators

· apply complementary protective measures?

– devices implementing emergency stop functions (selection of methods of implementation):

Method of implementation	Selection (X)
easy recognition, good visibility and easy access to control elements of the emergency stop device
a stop performed as soon as possible (without producing additional hazards) performed by a machine of the process producing hazards
triggering of relevant movements of the technical protective measure installed in the machine by the emergency stop machine or preventing such movements (e.g. activation of brake stopping the intrinsic movement of an element producing hazard)
maintaining the effect of machine stop signal activation until the moment the control element is reset (resetting should only enable the start-up of the machine and not re-start it)

– measures for energy disconnection and dissipation (selection of methods of implementation):

Method of implementation	Selection (X)
escape routes and shelters in plants posing hazard of entrapping of the operator
devices enabling manual movement of some of the elements, after emergency stop
devices enabling overturn of the movement direction of some of the elements
anchoring points of the devices for entering and getting down
communication measures enabling calling for help by entrapped persons
isolation (disconnection, separation) of the machine or relevant parts of the machine from any power supply sources
key-locking (or securing in other manner) of all the disconnecting devices in the disconnection position
dissipation or, if not possible or feasible, containment (absorption) of any accumulated energy that may produce hazard

– measures for handling the machines and their heavy elements (selection of methods of implementation):

Method of implementation	Selection (X)
standardised devices for lifting with loops, hooks, eyebolts or threaded holes for fixing these devices
devices for automatic pick-up with crane hook, if on-ground mounting is not possible
solutions enabling the placement of forks in proper place in the case of machines transported by means of pallet stacker trucks
in-built devices for lifting and stacking
devices securing the safety of taking out and fitting of spare parts of the machine during its operation

– measures for ensuring safe access to the machines (selection of methods of implementation):

Method of implementation	Selection (X)
ensuring, if possible, the performance of activities from the ground level
bridges, stairs or other devices ensuring safe access for the performance of activities
performance of pedestrian movement zones of non-slip materials in working conditions (to a greatest possible extent);
securing pedestrian movement zones at heights by using appropriate balustrades (if necessary, anchoring points for personal protection measures preventing falls from heights should be provided)
ensuring safety of access measures in large automated plants by using passages and walkways, transport bridges or junctions
opening closures opened in a safe direction, taking into account the risk of hazards produced as a result of their unexpected opening or closing
auxiliary access measures (e.g. steps, handles)
preventing (by means of proper design and placement) the use of control devices as auxiliary access measures
equipping the machine unloading levels for lifting of loads and/or persons with locking guards preventing falls from heights (in case of stopping at a level where no bridge is located); opening of these guards should be prevented by the movement of loading base

In the field “-Application of technical and complementary protective measures” (annex 1) a list of selected measures should appear

3.2 Whether as a result of these activities with respect to a given hazard:

Item	Question	Selection (X)
a	the risk connected with a given hazard shall be sufficiently limited (assessment according to D 4.2), which shall enable to avoid additional protective measures?
b	The risk connected with hazards shall not be sufficiently limited and the application of user information will be necessary?

To answer question a, a repeated risk assessment connected with a given hazard needs to be performed and upon taking into consideration all of the used technical and complementary protective measures (according to D 4.2). If the risk assessment is conducted, then in the field “Risk evaluation result (2)” an answer concerning the risk level appears (according to D 4.2).

If the action does not lead to the elimination of hazard or sufficient reduction of risk (point b) connected with the identified hazard, then it is necessary to take up actions defined in p. 4 and in the table in the field “Risk evaluation result (2)” an answer “unacceptable risk” will appear. In the case of an answer a, the risk reducing activities may be deemed completed.

4. Application of information concerning use

4.1 Is it possible to:

· apply information for the user?

– verbal information (selection of methods of implementation):

Method of implementation	Selection (X)
adequate content of the supporting documents (especially user manual)

– signals and warning devices (selection of methods of implementation):

Method of implementation	Selection (X)
application of visual and acoustic signals for warning against emerging event producing hazard, such as machine commissioning or excessive speed
application of visual and acoustic signals for warning the operator against automatic activation of protective measures
ensuring emission of signals warning before the hazardous event occurrence
ensuring uniformity of emitted signals
ensuring clear perception of emitted signals and their differentiation (from any other signals used)
ensuring clear recognition of emitted signals by the operator and other persons
ensuring the possibility of regular inspection of devices by means of their proper placement and construction, and also ensuring relevant information concerning their use
taking into account the possibility of sight and hearing sense overload in human during work (as a result of excess of visual and/or acoustic signals

– markings, symbols (pictograms) and warning inscriptions (selection of methods of implementation):

Method of implementation	Selection (X)
application of identification marking (name and address of the manufacturer, marking the batch or type, serial number – if any)
application of labelling confirming the compliance with applicable requirements (labelling and written information from the manufacturer)
application of labelling connected with safety during operation (maximum rotating speed of rotating elements, maximum tool diameter, weight of the machine itself and/or its removable parts, maximum working load, necessity of use of personal protection measures, data concerning regulation of guards, data concerning the frequency of inspections)
ensuring that the information placed directly on the machine is durable and legible throughout the whole expected life cycle of the machine
ensuring that labelling, symbols and warning inscriptions are easy to understand and unambiguous
preferred easily understandable symbols (pictograms) to warning inscriptions

In the field “-Application of information concerning use” (annex 1) a list of selected measures should appear

4.2 Whether as a result of these activities with respect to a given hazard:

Item	Question	Selection (X)
a	the risk connected with a given hazard shall be sufficiently limited (assessment according to D 4.2), which shall enable to avoid another risk assessment (e.g. after the change in the machine structure)?
b	The risk connected with hazards shall not be sufficiently limited and another risk assessment will be necessary (e.g. after the change in the machine structure)?

To answer question a, a repeated risk assessment connected with a given hazard needs to be performed (according to D 4.2). If the risk assessment is conducted, then in the field “Risk evaluation result (3)” an answer concerning the risk level appears (according to D 4.2).

If the action does not lead to the elimination of hazard or sufficient reduction of risk (point b) connected with the identified hazard, then it is necessary to perform another risk assessment connected with the hazard (according to D 4.2) and upon taking into consideration all of the protective measures applied and in the table in the field “Risk evaluation result (1)” an answer “unacceptable risk” will appear. In the case of an answer a, the risk reducing activities may be deemed completed.

5. Application of information concerning use

After sufficient elimination of occupational risk, in the table in annex 1 in the field “Residual risk” information concerning the residual risk connected with hazards with respect to which the risk reduction was performed, along with the notes, should appear.