Maintenance and inspection programs for chairlifts and
aerial ropeways
Purpose of this guidance note
To advise an employer who has management or control
of a chairlift or aerial ropeway of the need to ensure the integrity of the
chairlift or aerial ropeway through effective maintenance and inspection
programs. (From now on a reference in this guidance note to "employer"
will mean the employer who has management or control of a chairlift or aerial
ropeway.)
Need for a maintenance program
People riding chair lifts and aerial ropeways are
subject to a relatively high degree of risk in the event of a malfunction or
failure of a critical component. Accordingly, employers need to take all
practicable steps to ensure the equipment is maintained in good working order; a
methodical approach to inspection and maintenance of chair lifts and aerial
ropeways over the life of the plant must be in place.
What are the important features of a general
maintenance program for chairlifts and aerial ropeways ?
The maintenance program requirements must be
identified during the hazard identification, risk assessment and risk control
process as required by the Occupational Health and Safety (Plant) Regulations
and the associated Code of Practice for Plant (see under the "Further
information" heading for details on obtaining the regulations and code.)
These requirements should address any information provided by the designer or
manufacturer and also incorporate requirements that may be unique to the
particular chairlift or aerial ropeway. There are also some specific features of
the general maintenance program which must be included - these will be described
below. (Later in this guidance note there will be guidance on things which
should be included in a specific maintenance program for chairlift and aerial
ropeway towers.)
The Code of Practice for Plant recommends that the
maintenance program should be compatible with Australian Standard AS 3533 Part
2. That Australian Standard, in turn, calls up various Canadian Standards (eg
CAN/CSA-Z98-M91 or Z98-01). However, there are a number of general
considerations that have to be included in the maintenance program.
The maintenance program must include systems to
identify potential safety issues so that necessary corrective action can be
taken before the failure of a component.
If the designer or manufacturer of the plant has
provided a maintenance program, that program should be adhered to by the
employer. If this maintenance information is not available, the employer must
ensure that a comprehensive maintenance program is developed, documented and
implemented which includes relevant daily, weekly, monthly and annual or
seasonal maintenance activities.
The development and documentation of the
maintenance program should be undertaken by a person with suitable knowledge and
experience in the commissioning and maintenance of chairlifts and aerial
ropeways.
The employer must ensure that the maintenance
program includes procedures for addressing all components subject to load, wear,
corrosion or fatigue. This would include:
- the types of lubricants required and
frequency of application;
- the types of non-destructive testing required
and frequency of testing;
- destructive testing and frequency of testing;
- the definitions and measurements to determine
excessive wear and replacement criteria;
- the recommended frequency of service to
specific parts and details of the service required; and
- identification of other areas that might
require specific attention.
Regular inspections must address:
- ride access by passengers, maintenance and
operational staff;
- safety during the ride;
- fundamental mechanical and electrical safety;
- fire safety;and
- noise
The types of inspection activities must include the
following:
- commissioning inspection including load test
runs;
- formal pre-season inspection;
- daily and periodic maintenance inspections;
- annual inspection (or at change of ownership);
- periodic major inspection of critical
components;
- designer and manufacturer stipulated
inspections;and
- ancillary equipment inspections
Although many of the above may be performed
visually, visual inspection alone cannot always be used to identify structural
faults and wear.
The following testing must be carried out:
- load testing at 5 yearly intervals or at
change of critical load bearing components;
- non-destructive testing; and
- destructive testing (ropes)
All non-destructive testing must be carried out by
a suitably experienced person and in accordance with relevant Australian
Standards.
Procedures must be developed (and regularly audited)
for:
- daily start-up, running and shut-down;
- daily and periodic maintenance;and
- environmental conditions
When should maintenance inspections occur?
Major inspections must be done in accordance with
the scheduled major maintenance inspections recommended by the designer or
manufacturer (if those recommendations are available) and any further
inspections identified by the employer. Major inspections must also be done
following major failures, recommissioning, upgrading, or a change to the
original design which alters any major component of the plant. Non-destructive
testing of critical components of the plant may be necessary in locations where
environmental conditions (eg. corrosive or thermal effects) are particularly
severe.
Particular considerations for a maintenance
program for chairlift or aerial ropeway towers
Particular attention must be given to towers
greater than 20 years of age or where the design of the equipment is not in
accordance with the technical standards mentioned earlier in this guidance note.
In these circumstances, the employer must make sure the maintenance program
includes regular tests (eg. torque tests or visual inspection) to check for
fatigue or corrosion of the anchor bolts on a sample tower. This may require the
tower to be lifted free of its anchor bolts.
Consideration must also be given to whether the
towers and anchorage system have been subject to any random vibration due to
movement of the haul rope and carrier grips over sheave assemblies and other
factors that may have an impact on the effectiveness of anchor bolts such as:
- whether a continuous uphill load imposed by
the subtended angle of the haul rope on any vertical tower might lead to
excessive fluctuating loads on the anchor bolts; or
- whether tower base plates that are not fitted
directly to the concrete footing have incorporated expanding grout between
the tower base plate and the upper surface of the concrete footing to allow
a continuous tension load on the anchor bolts to be maintained.
As well, towers that have bracing tubes around
anchor bolts connected to the main tower tube by a gusset should be subject to
detailed investigation for water retention and resultant corrosion.
In addition to any testing and inspection of
safety-critical components specified by the designer or manufacturer, the
following should be considered for inclusion in the maintenance regime for
towers:
- Column, including foundations and anchor
bolts:
- Visual inspection for deterioration of
the foundation or possible deterioration of the supporting ground
- Inspection of the grout between the tower
base and the foundation to identify any deterioration in the condition
of the grout and it's effective weatherproofing
- Testing of the anchor bolts and tower
base plates or welds for corrosion and cracking using non-destructive
testing or other appropriate test systems
As anchor bolts cannot be visually
inspected, test torquing using an appropriate torque wrench to the
manufacturer's recommended annual torque requirements may be required
to confirm the anchor bolts continued ability to anchor the tower.
Where deterioration of the foundation
or supporting ground is observed or an anchor bolt cannot sustain the
test torque or non-destructive testing indicates excessive corrosion
or cracking in the tower base assembly, the chairlift must not be used
until accurate determination of the towers ability to sustain the
loads within design limits has been established. This might require
dismantling and replacement of the tower and its foundation.
- Sheave assembly tower crossheads, rope
lifting frame, and service platform, access ladder and rungs:
- Non-destructive testing to detect
internal corrosion.
- Crack detection on load critical welds.
- Replacing, or where appropriate
re-tensioning, of any bolts in the tower column, tower crossheads or
frames
Particular considerations for maintenance
program on major components and systems
In addition to the tower maintenance procedures
detailed above, maintenance procedures must address the major components and
systems. The following is a brief overview:
- Chair, Hanger and Rope Grip assembly
- Ropes
- Haul Rope
- Counterweight Tension Rope
- Guy Ropes or Stays
- Rope Tensioning Equipment
- Communication and safety systems including
emergency stop
- Drives
- Main Drive
- Standby Drive
- Rescue Drive
- Integrity of power source for all drives
- Sheave assemblies and rope guiding
equipment
- Line sheave assemblies, sheave bearings and
liners
- Alignment
- Bull wheels
- Drive and return sheaves, bearings and liners
- Rope guiding equipment
- Alignment
- Brakes
- Service Brake
- Emergency Brake
- Anti-rollback systems
- Backstops and anti-rollback brakes
- Loading and unloading stations and
equipment
- Safety Gates
- Fire fighting equipment
- Inspection and testing requirements in
accordance with Australian Standards
- Electrical systems and equipment
- Earthing systems
- Control and monitoring devices
- Emergency evacuation – procedures and
equipment
- Corrosion protection
- Control of water condensation and drainage,
and identification and elimination of water retention areas.
Legal responsibilities
The Occupational Health and Safety Act 1985
requires employers to ensure a work environment that is, so far as is
practicable, safe and without risks to health of employees. This duty includes
ensuring safety in provision and maintenance of plant and systems of work. The
Act also requires employers and self-employed persons to ensure, so far as is
practicable, that the conduct of their undertaking does not expose persons other
than employees to health and safety risks. Plant Regulations made under the Act
impose specific duties on employers including hazard identification, risk
assessment and risk control in relation to plant, and inspection and maintenance
of plant.
Under the Equipment (Public Safety) Act 1994 and
associated regulations, similar duties are imposed on proprietors of prescribed
equipment at sites that are not workplaces.
Non-compliance with legislative duties is an
offence and can be subject to prosecution and significant penalties.