Updated: May 27, 2021
International Climbing and Mountaineering Federation
UNION INTERNATIONALE DES ASSOCIATIONS D'ALPINISME
STRESS CORROSION CRACKING
FAILURE OF CLIMBING ANCHORS
UIAA 123 standard update, 2020
國際山岳聯盟《攀岩錨栓安全規範 (UIAA 123)》
翻譯：王大濟 | Translation by Ta-Chi Wang
UIAA Safety Commission 2020 | firstname.lastname@example.org
The UIAA Safety Commission is composed of national federation delegates, manufacturers and accredited testing laboratories.
The subject of corrosion and stress corrosion cracking failure has been a work in progress for the last ten years within SafeCom. December 2020, the Commission is able to release the resultsand update its Standard UIAA 123 Rock Anchors V4_2020. This major update is based on scientific research performed by Brest (France) and Prague (Czech Republic) laboratories, coordinated and funded by the UIAA, for the safety of all climbers worldwide.
This Standard has been updated based on SafeCom’s best knowledge of atmospherically induced stress corrosion cracking, i.e. with respect mainly to chloride resistance. Nevertheless, in some locations and environments this is not the appropriate procedure and where additional tests need to be performed, e.g. under high sulphate content. Further research is ongoing to gain a clearer understanding of this phenomena and how to determine which locations are concerned.
UIAA 安全委員會 係由會員 (國家級山岳聯盟) 代表、製造商、和經由 UIAA 認可的實驗室組成。
過去十年來，UIAA 安全委員會一直都在進行一般腐蝕以及應力腐蝕研究。2020 年 12 月，安全委員會終能公佈研究結果並更新 UIAA123 攀岩錨栓 V4_2020 規範。此更新主要是基於 UIAA 主持並資助的布雷斯特 (法國) 和布拉格 (捷克共和國) 的實驗室科學研究，以確保全球登山者以及攀岩者的安全。
此次更新是根據 UIAA 安全委員會針對「環境引發應力腐蝕」，亦即針對氯化物為腐蝕原因之最佳知識所定。但，在一些地區或特定環境，氯化物並不是唯一原因，例如在含高硫酸鹽的環境也可能發生應力腐蝕，關於後者，相關測試以及研究是必要的，也正在進行，以更清楚了解環境引發應力腐蝕的原因，並用以判斷可能發生的區域。
Reminder of the quick facts
Recent incidents indicate unexpected failures of climbing anchors after beingset-in place for a few months/years and under low loads. These failures occur mostly on stainless steel anchors due to environmental degradation, i.e. corrosion and more specifically stress corrosion cracking (SCC).
In worst cases, anchors can break under the weight of ten to twenty kilograms –obviously less than the average climber’s weight.
Usually in coastal locations, but even up to a few kilometres away from the coast.
All material in warm coastal areas shall be considered as potentially affected
Corrosion is not always visible and can occur in cracks not seen by visual inspection.
Stress corrosion cracking is the most virulent and canvery rapidly initiate cracks shortlyafter anchor
installation. In some cases, within a few months and almost certainly within a few years.
All metallic anchors, including parts made of stainless steel or aluminium alloys are impacted, except those which are rated UIAA 123-SCC.
The most critical factors are:
“Moderate” relative humidity locations (The very dry and very humid locations are OK, it is the in-between the two extremes that is a problem).
Areas NOT being washed clean by a rainfall (even being washed by the sea can be OK!).
Temperature: SCC can occur at 20°C, higher temperatures are worse.
最壞的情況，錨栓可在遠低於登山攀岩者平均體重的 10 至 20 公斤荷重下斷裂。
其中應力腐蝕 (SCC) 最危險，可在安裝錨栓後不久迅速引發，在某些情況下，幾個月內即可能發生，至多幾年即會引發。
除 UIAA 123-SCC 等級認證的金屬錨栓外，所有金屬錨栓，包括任何不銹鋼或鋁合金零件， 均可能引發應力腐蝕。
溫度：應力腐蝕可在 20°C 時發生，溫度愈高可能性愈高。
What are the main changes?
The list of acceptable materials for the most corrosion resistant class have been removed.
The new Standard now tests the complete anchor to ensure as much as possible the stresses it may endure upon installation.
The highest corrosion resistance classis Stress Corrosion Cracking (SCC)
The UIAA Safety Label certificate is given to anchors that have successfully passed the general corrosion and Stress Corrosion Cracking (SCC) tests as per Table 1.
新標準最高的耐腐蝕等級為耐應力腐蝕 (SCC–Stress Corrosion Cracking)
UIAA 安全認證將授予通過一般腐蝕和應力腐蝕相關測試之錨栓，請見表 (1)。
Table 1: UIAA 123 Rock Anchor V4_2020
Classes and Environment Characteristics
表 (1)：國際山岳聯盟《攀岩錨栓安全規範》第四版 2020
Why testing the complete anchor?
Influential factors: amount of internal Stress and resistance to SCC
the manufacturing method: bending, welding, cutting, drilling, even laser engraving adds a significant amount of internal stresses.
the installation: expansion anchors are subject to additional stress when screwed in place. Hammering with any metallic tool is also very detrimental and should be avoided.
This is why during testing the screw-in anchors are installed in a granite block as per manufacturer's instructions for use and installation. For glue-in anchors (it is considered that the glue does not induce significant stress), they are fully immersed in the solution.
Why three classes?
為何分 3 等級?
The lastest research reveals that defining classes by only the material type is not pertinent since some anchors made of low SCC resistant alloys (e.g. 316L) could pass the test while other anchors made of high- end SCC resistant material do not pass the same test. This is mainly because the stress on the anchors from different manufactures could vary.
For these reasons, it has been decided to have three classes, and only one of them with resistance to SCC.
最新研究顯示，用材料種類來定義抗腐蝕等級並不適合，因為某些抗應力腐蝕能力低的合金所製成的錨栓 (例如 316L) 可通過測試，而某些抗應力腐蝕能力高的材料所製成的錨栓卻無法通過相同測試，就因爲不同廠商之製程所造成的內應力不同。
What is Stress Corrosion Cracking?
Stress Corrosion Cracking (SCC) is a very virulent type of corrosion that could provoke cracks very rapidly. Contrary to general corrosion, which generates sufficient amounts of well visible corrosion products such as rust, SCC can usually not be detected during on-site visual inspection. Many stainless steels, aluminium alloys and other metallic materials are affected.
SCC is influenced by many different factors, as presented in Table 2.
Table 2: Factors contributing to
stress corrosion cracking of climbing anchors
Which locations are affected?
Potentially all coastal areas could be affected by atmospheric induced stress corrosion cracking, including up to several kilometres from the coast.To this day, it is still not possible to clearly distinguish affected locations from safe ones. The variation of many parameters as presented in Table 2 can influence the corrosion conditions. For example, the wind can blow salt over hundreds of kms inland, and beyond the reach of sea breezes the rock itself can contain the ions that promote SCC.
The UIAA has created a Map of known corrosion locations. This map is intended only as a reference to identify areas where examples of corrosion have been logged. It is designed only as an informative guide based on data received and assessed. It is not intended as a complete reference and is subject to changes beyond the UIAA’s control.
To support the UIAA Safety Commission with its analysis and to help add more areas to the map thereby improving the information available to climbers about dangerous or potentially dangerous areas to climb, a dedicated form is available to share information about corrosion or failed anchors.
沿海地區，包括離海岸數公里的區域，都可能受到「環境引發應力腐蝕」所影響。迄今仍無法清楚界定會受影響或安全的界線。如表 (2) 所示，許多因素都有變數，譬如，風可能挾帶海鹽至內陸數百公里處，即使海風不能及，岩石本身也可能含有可觸發應力腐蝕的電離子。
UIAA 建立了 已知應力腐蝕發生區域地圖，但此地圖僅供參考，目的是記錄應力腐蝕實際發生地區。該地圖是接收各方資訊並評估最新訊息而設計的參考指南，因此其內容並非由 UIAA 所掌控，也不是完整資料，內容隨時可能異動。
為了支持 UIAA 安全委員會在這方面的分析，並協助地圖上的訊息更完整，從而改善攀岩者可能面對的危險或潛在危險，請使用此 專用表格，共享有關錨栓腐蝕或失效的資訊。
What you should know when installing bolts
Use only UIAA123 – SCC class certified anchors. This class for locations where SCC is common. In case of doubt and for areas with rare incidence of SCC or areas where SCC is suspected but not documented always choose the highest class.
Do not combine bolts, nuts, washers or hangers of dissimilar metals, because galvanic corrosion could be initiated due to the different electrochemical potentials.
Use a calibrated torque wrench to fasten the nut in order to avoid plastic deformation of the material and to keep the axial stress at moderate levels, as suggested by the manufacturers.
If possible, regularly inspect the material(s) in place.
If corroded anchors are found, contact the UIAA.Failed anchor parts can be sent to to the UIAA or one of its national federations for analysis: https://theuiaa.typeform.com/to/rlBZyc
在應力腐蝕發生過地區或應力腐蝕發生率低但懷疑可能會發生地區，請使用 UIAA123 – SCC 認證的錨栓。
勿混用不同金屬 (或不同等級金屬) 的螺栓、螺母、墊圈或耳片，因為不同類別金屬接觸所造成之電化電位差將導致電流腐蝕。
如果發現鏽蝕的錨栓，請跟 UIAA 聯絡，失效錨栓可送至 UIAA 或在地國之 UIAA 會員組織進行分析: https://theuiaa.typeform.com/to/rlBZyc
How to check when climbing?
The UIAA123 V4_2020 Standard states that the anchors shall be marked with the letters UIAA followed by the class SCC, GC or LC as per Table 1.
Evaluating the risk due to SCC is almost impossible for individual climbers because SCC degradation is often not visible. Only destructive testing can confirm the presence/absence of SCC on installed anchors. Even anchors that have been installed in recent months and/or look brand new could be compromised by SCC or some forms of corrosion.
SCC is very difficult to predict as it depends on a complicated set of factors, especiallyelevated temperature, low humidity, and formation of magnesium -or calcium- rich chloride deposits at unwashed locations (Table2). Small differences in microclimate can lead to SCC degradation for some bolts, while other bolts on the same climb are unaffected. SCC is associated with seaside climbing but can also occur in inland areas where corrosive elements are present, either naturally occurring in the rock itself or deposited inland by sea breezes.
所有通過 UIAA123 V4_2020 規範的錨栓，均有「UIAA」標示，及表 (1) 所示 SCC、GC、或 LC 等字樣。
應力腐蝕很難預測，因為它取決於一些複雜因素，尤其是高溫、低濕度、以及鎂或鈣的氯化沉積物不易清洗之處 (見表 2)。局部環境的微小差異會導致某條路線上一些錨栓發生應力腐蝕，但其它錨栓卻不受影響。應力腐蝕固然與海邊有關，但也可能發生在內陸，只要該區的岩石本身具有腐蝕因素，或海風能將腐蝕因素帶進該地並累積。
Recommendations for climbers
給登山 / 攀岩者的建議
When planning a trip
Consider SCC when assessing the risk of climbing at a proposed climbing destination.
Check with local climbers and/or climbing organizations regarding the prevalence of SCC and the corrosion resistance of local bolts.
Be prepared for the presence of SCC, especially at hot, seaside destinations.
Consider SCC when assessing the risk of climbing a given route.
Belay/lower from redundant, multi-bolt anchors.
When in doubt, accept the need to back up bolts and belay/rappel stances with nuts, camming devices, trees, and/or threaded hour glasses.
Be prepared to abandon projects with suspect bolts.
In the event of bolt failure (once the climbers are safe and injuries have been attended to)
Collect the failed anchor parts; avoid disturbing the failure surface or trying to piece together the failed anchor.
Inform the local climbing community.
Contact the UIAA. Faulty/failed anchor parts can be sent to the UIAA or one of its national federations for analysis: https://theuiaa.typeform.com/to/rlBZyc
確保 / 下放時，使用設有二個以上錨栓的固定點。
如對錨栓有疑慮，使用岩楔或天然地形 / 地物架設備份系統。
與 UIAA 聯絡，失效錨栓可送至 UIAA 或在地國之 UIAA 會員組織進行分析：https://theuiaa.typeform.com/to/rlBZyc
What climbing organizations should know
登山 / 攀岩組織應知
SCC and/or corrosion and the aging of existing bolts present challenges to the climbing community that cannot be met by individual climbers.
The main obstacles to use of SCC and/or corrosion resistant anchors are cost and availability. Individual bolters can be short of funds, and somewhat reluctant to spend even more of their own money. When a bolting fund is available to provide funding, the bolters are always happy to use the more resistant anchors.
This means that the bulk of the climbing population needs to start paying more for anchors, whereas in the past most climbers had a “free ride”.
Bolting new climbs and re-bolting existing climbs to address the risks of both general corrosion and SCC will require significant investment of both time and money for the installation of new bolts that are appropriately corrosion resistant. This initial cost is offset by the increased lifespan of the resulting bolts and the decreased incidence of accident and injury.
Quality control (QC) measures are necessary for responsible long-term management of bolts, especially documentation of both anchor failures and anchor installation dates & types.
Monitoring of bolt integrity (pull testing of off-route bolts) is similarly important. Record keeping for these QC measures must be in place for 50+ years.
應力 / 或其它類型腐蝕，以及老舊錨栓對整體登山 / 攀岩社群的挑戰，個人無法應對。
使用抗應力腐蝕 / 抗其它腐蝕錨栓的主要障礙是成本和可得性。個人的錨栓更新行動普遍缺乏資金，但當有錨栓資金可用時，錨栓更新工作者總是樂於使用抗腐蝕性更高的錨栓。
這意味著絕大部分的登山 / 攀岩社群要準備為錨栓支付更多的費用，而在過去，大多數攀岩者都享受免費的「便車」。
有效的地方性長期錨栓品質管控 (QC) 是必要的，特別是建立錨栓失效、安裝日期、和錨栓類型等相關紀錄。
錨栓品質監控 (例如拉力測試) 同樣重要，以上這些錨栓品管記錄必須保持 50 年以上。
The UIAA Safety Commission urges national federations and local climbing communities to plan a future that includes responsible management of bolt corrosion and that asks for UIAA 123 V4 certified products.
UIAA 安全委員會期許各國會員和各在地攀岩社群妥善計劃更好的未來，包括進行妥善的錨栓鏽蝕管理並使用 UIAA 123 V4 認證產品。
JiříLieberzeit, TomášProšek, Alan Jarvis, Lionel Kiener,
Atmospheric Stress Corrosion Cracking of Stainless Steel Rock Climbing Anchors, Part 1, CORROSION. 2019;75(10):1255-1271.
TomášProšek, JiříLieberzeit, Alan Jarvis, Lionel Kiener,
Atmospheric Stress Corrosion Cracking of Stainless Steel Rock Climbing Anchors, Part 2: Laboratory Experiments, CORROSION. 2019;75(11):1371-1382.