Bolting Standard
The CCA Bolting Code of Practice provides guidance for bolting in
recreational canyoning situations.
Anyone considering placing bolts in Canadian canyons should ask themselves
these questions:
• Are we allowed to bolt?
• Should we bolt?
• Who should do the bolting?
• How do we bolt?
Bolts that do not meet the legal, ethical or safety standards of this code of
practice should be removed or replaced as soon as is practicable
Disclaimer
Whilst every effort has been made to ensure the accuracy of the information in this
document, the authors and the CCA accept no responsibility or liability for loss or
damages in relation anyone’s interpretation or use of this code of practice.
This document is not intended to provide definitive advice on canyon anchors. The
extreme variability of rock characteristics in the natural canyon environment make
that impossible. Installing safe anchors requires considerable knowledge, judgement
and skill.
This document is not a substitute for the practical training and experience which is
required to gain that knowledge, skill and judgement. The purpose of this document
is to raise the awareness of those who are considering bolting of the known issues,
and to offer guidance on good practice to address those particular issues.
Are we allowed to bolt?
Anyone considering bolting for recreational canyoning is encouraged to contact The Canadian Canyoning
Association (CCA) for further guidance or assistance liaising with stakeholders.
Permission must be gained from the landowner and/or land manager. Local x should be
consulted where relevant. For conservation land, the relevant management plans should be
consulted before seeking permission from the Department of Conservation or other relevant Land Authority.
Should we bolt?
Before placing any bolt, we must think very carefully about the long-term impacts on the canyon
and surrounding environment, as well as the impacts on the activity of canyoning. Bolting is only
appropriate if the benefits outweigh the impacts.
The CCA will assist in obtaining the views of the relevant canyoning community and other
stakeholders on whether bolting is appropriate for a particular canyon or canyoning area.
Permanent bolts
Any bolts in canyons that are likely to be repeated should be of permanent bolt standard.
Permanent bolts must have a sufficient margin of safety for all reasonably expected uses of that
anchor. They must be made of quality, highly corrosion resistant materials and of sufficient
strength to maintain the margin of safety for many years. Minimum construction standards and
acceptable permanent anchor types are detailed later in this document.
The type of bolts and year of installation should be recorded and included in CanyonTopo
diagrams and descriptions to aid in monitoring the scope and quality of bolting in Canada Canyons.
Canyons that, due to high flows, would require an excessive number of bolts (to establish a
contrived line clear of the water) should not be bolted.
Temporary bolts
Temporary bolts are acceptable for a single use and in the following circumstances only. If the
canyon is likely to be repeated, any temporary bolts must be removed or upgraded to permanent
bolt standards as soon as possible. Minimum construction standards and acceptable temporary
anchor types are detailed later in this document.
• Exploration/first descent bolting - During exploration, bolts may be placed as a last
resort where there is no other practical means of descending or escaping the canyon.
When the location, length and difficulty suggest that the canyon descent may be repeated
in the future, the temporary bolts should either be readily removable (temporary) or meet
the technical standards for permanent bolts. Lower strength or quality bolts that cannot be
removed are not acceptable for exploration of canyons which are likely to be repeated.
• Emergency bolting - When existing bolts have been damaged or destroyed without the
knowledge of a canyoning group, it is acceptable to place emergency bolts as a last resort,
where there is no other practical anchor to use in order to escape the canyon.
Who should do the bolting?
Bolts should only be placed by competent people with experience in the current bolting techniques.
Those people should be familiar enough with the canyon that they are able to choose the most
suitable locations for anchors. Those that place the bolts have a moral obligation to ensure
anchors are as safe as is reasonable for the situation. Individual users must accept all risks when
using an anchor placed by others.
How do we bolt?
Bolting considerations
When bolting, we must ensure that the anchors:
• Meet the minimum construction standards.
• Are placed using the correct installation principles.
• Are placed in suitable rock.
• Are place in a suitable position.
Minimum construction standards for anchors
Permanent anchors
• The complete anchor system must have a minimum ultimate strength of 20kN.
• Each bolt must have a minimum ultimate strength of 20kN.
• All anchor components must be constructed of the same material, being 316 (or better)
Stainless Steel.
Temporary anchors
• The complete anchor system must have a minimum ultimate strength of 15kN.
Installation principles
• Two bolts must be used for abseil anchors and the start of handline anchors. A single bolt
is acceptable for intermediate handline anchors.
• Bolts must be installed according to the manufacturers guidance.
• Ensure the anchor site is in sound rock, at least 1.5x the bolt length away from any fissures
or cracks.
• Check the rock surface before drilling, to ensure hangers will sit flush with the rock.
• Hangers must not be loose or able to spin.
• The bolt should not protrude excessively.
• Double bolts must be at least 2x the bolt length or 200mm apart (whichever is greater).
Positioning of anchors
Anchor stations should be positioned such that:
• They are easily reached by a canyoner of average height and with appropriate skill for the
grade of canyon.
• They are reachable from or via a durable surface, in all reasonable flow conditions.
• They are positioned such that it is difficult for a careless canyoner to shock load or
incorrectly load the bolts.
• The bolts are oriented in a way that allows the use of single rope technique, minimises
wear on the rope and allows for easy retrieval.
• They encourage a line of abseil descent which is on a durable surface and minimises the
risks of hydraulic danger in all reasonable flow conditions.
• They are protected from damage in floods by being clear of the anticipated current and
flood debris.
• Space is available for possible future upgrade or replacement of the anchors.
Assessing the suitability of the rock
Assessing the strength of rock in a canyon is highly subjective, and whenever there is any doubt
that the rock is hard enough for mechanical bolts, then chemical bolts should be used.
Check the hardness and uniformity of the rock using a bolting hammer. Feel for the ‘bounce back’,
listen for the noise and watch for any deformation/cracking.
Ensure you have a clear view of the rock surface, then visually scan within an arm length circle
around the intended site to look for deformities, cracks or weak layers. Check that the rock is part
of the canyon, not a loose block or detached flake.
• For rock greater than approximately 50MPa: Suitable mechanical anchors will likely meet
the strength requirements.
• For rock between approximately 25-50MPa: 10mm eye bolt chemical anchors will likely
meet the strength requirements.
• Less than 25MPa: There is insufficient evidence to be able to give a good recommendation
on choice of anchors.
Acceptable permanent anchor types
Expansion bolt (Collar-Stud)
10mm is typically the minimum diameter required for an expansion bolt to meet the
permanent anchor construction standards of 20kN. Expansion bolts should be at least
75mm in length for very hard rock, longer in less hard rock.
Expansion bolts are not removable, and while they can be rendered unusable and hidden
(by tapping in to an over-drilled hole), the same location cannot be used for future
permanent bolting. Expansion bolts should therefore be avoided for emergency or
exploration use in any canyon which is likely to be repeated. An acceptable exception is if
they are extremely carefully situated, so they can be used for the long term by future
canyoneers.
Chemical Anchors
Chemical anchors are the best solution for softer rock. P bolts and Eye bolts which are
specifically designed for climbing anchors are the most appropriate types of chemical
anchor for canyoning.
They require a practical minimum diameter of 10mm to meet the permanent anchor
construction standards. The minimum recommended bolt length is 75mm in hard rock,
100mm in soft rock.
The adhesive used should be a high-quality adhesive specifically designed for structural
anchoring applications.
The hole should be thoroughly cleaned; the strength of the bolt is proportional to how well
the hole is cleaned.
The head of an Eye or P bolt should be recessed into the wall to reduce any torque loads
on the glue bond.
Acceptable temporary anchor types
Sleeve anchors
Sleeve anchors are appropriate temporary anchors because they can usually be
removed, although damage to the hole is possible. The load bearing part (stud) of the bolt
is thinner than it appears, which must be taken into account if using this type of anchor.
A practical minimum bolt diameter of 10mm, gives an 8mm stud and approximately 15kN
ultimate strength. Sleeve anchors should be at least 75mm in length
Screw anchors
Screw anchors can easily be removed. The same hole can then be drilled again with a full
diameter bit and a permanent bolt placed if required.
A practical minimum dimension of 7.5mm x 60mm corresponds to 18.6kN shear strength
Self-drilling anchor
Self-drilling anchors cannot be removed and there is very little margin for error when
placing them. However, they may be considered acceptable in cases when it was not
anticipated that bolts would be needed and a lightweight hand drill kit was carried for use
as a last resort.
Quicklinks (maillons) and rappel rings
These must be manufactured specifically for climbing and have been tested by the
manufacturer to meet the appropriate (temporary or permanent) anchor construction
standard. Non-rated chain links, D-shackles or quick links are not acceptable.
When used as the focal to thread the rope through, the internal dimension should be
large enough to allow common rope diameters to be threaded and retrieved easily, but
small enough to prevent a carabiner passing through (ie, when using a carabiner block).
Common rope diameters are 9-10mm. The gate on a quicklink should be tightened firmly
with a spanner.
Bolt hangers
Ring hangers should be regarded as the standard for all permanent canyon anchors that
use expansion bolts.
Hangers must be designed for height safety use and the hole in hanger must match bolt
diameter. Hangers must have either the manufacturers name and rated strength, or
UIAA/EN symbol/certification stamped on them.
Anchor linking materials
Chain
Steel chain that is sold by the meter must be 316 stainless steel or better, must be grade
80 or above, “approved for overhead rigging” and have a rated strength from the
manufacturer. Purpose built climbing “belay stations” must meet EN959/UIAA123
standards.
Placing the chain directly between the rock and the nut/head of a bolt is not acceptable,
even when using a washer. The width of the chain places an additional bending moment
on the bolt stud, which results in a weaker anchor.
Webbing
Only 25mm or 16mm tubular webbing conforming to EN565 is acceptable.
The ultimate strength of webbing configuration must be calculated to ensure it meets the
minimum anchor construction standards (temporary or permanent). Webbing can be tied
directly through bolt hangers provided there are no sharp edges. The tail of any knot can
be used to ‘pad’ the hanger.
Rope
Offcuts from core-shot canyoning abseil rope may be used, provided the rope is still fit for
use (no mechanical damage/fraying or UV damage).
When tied, the ultimate strength of the rope/anchor configuration must be calculated to
ensure it meets the minimum anchor construction standards (temporary or permanent).
Dyneema Cord
The use of Dyneema cord is only acceptable for temporary (exploration) anchors, on very
long and/or remote canyons where at least one night is planned to be spent in the
canyon. Any expedition considering the use of such anchors should contact the NZCA to
discuss their plans.
Anchor configurations
When choosing a anchor configuration, consideration should be given to:
• The direction of the load throughout the pitch.
• The location of suitable rock to place a bolt and the anchor as a whole.
• The exposure of the anchor to flood water or air turbulence caused by flood waters.
• The ease of retrieval of the rope.
Y hang configuration
This is the preferred configuration when canyon geometry could make rope retrieval
difficult.
The angle between anchor arms should be less than 60 degrees (60% on each arm).
Inline configuration
This configuration has the advantage of using less linking material (chain or webbing)
than the Y hang configuration, while still facilitating easy rope retrieval in most cases.
The linking material should be attached to the lower maillon/ring and be tight between the
anchors when loaded. This ensures the load is shared as evenly as possible between the
anchors.
The proximity of the lower bolt to the rock may cause rope to be pinched on retrieval if not
carefully situated.
Independent configuration
This is the preferred configuration for chemical anchors, or anywhere the anchor is likely
to be exposed to flood water (or air turbulence caused by flood waters).
When using P or Eye bolts, the lower bolt should be oriented 90 degrees to aid rope
retrieval (see image; arrow indicates direction of load).
This configuration may also be used with symmetric ring hangers. Double bolts with
maillons or parallel rings are usually not suitable as they hinder rope retrieval.
May require temporary linking with a quickdraw, or similar, to provide redundancy