结论：警示要被看到、看懂、并被执行，三者缺一就无效
警示标识是风险控制措施的一种，但它在风险控制措施中的可靠性是较低的 ——因为它依赖使用者去看、去理解、去遵守。
一个警示要真正起作用，需要三个条件同时满足：
被注意到。 在相关操作时能被看到。
被理解。 使用者明白它说的是什么、为什么。
被执行。 使用者愿意并能够按警示行事。
三者缺一，警示就没有起到风险控制的作用。 而验证有效性，就是验证这三个条件。
风险控制的层次
在风险控制中，措施的可靠性有层次：
设计上消除。 从根本上去掉风险。这一层最可靠。
防护措施。 结构上防止危险发生。可靠性较高。
警示信息。 依赖使用者。可靠性较低。
所以警示不应当是优先的控制手段，只有在前两者不可行或不充分时才依赖警示。
实务中的常见问题是：能通过设计解决的问题用警示代替。 比如某个部件容易装反，正确的做法是设计成装不反（防呆），而不是贴个标签说「注意方向」。
被注意到的条件
位置。 在相关操作的视线范围内。贴在使用者看不到的位置等于没贴。
大小。 足够引起注意。
对比。 与背景的视觉对比。
时机。 在使用者需要这个信息的时候出现。
不被遮挡。 使用中不被其他部件或附件遮住。
数量适度。 标识过多会降低每一个的注意度。
「不被遮挡」是实际中常见的问题。 标识贴在车架上，装了坐垫或选装件之后被挡住了，使用者根本看不到。
「数量适度」值得注意。 一个产品上贴十几个警示标识，使用者会忽略全部，反而不如只保留最关键的几个。
被理解的条件
表述清楚。 说明危险是什么、后果是什么、应当怎么做。
语言适当。 目标使用者能理解的用词。
图形符号的使用。 通用的符号比文字跨语言效果好，但要用公认的符号。
避免歧义。 表述不应有多种理解。
信息完整。 只说「危险」而不说什么危险、怎么避免，作用有限。
「说明怎么做」是容易被省略的部分。 「警告：可能造成跌倒」不如「警告：上下斜坡时可能翻倒，坡度不应超过某值」有用，后者告诉了使用者具体该怎么做。
被执行的条件
要求的可执行性。 警示要求的行为使用者能做到。
不与使用便利冲突。 如果遵守警示明显增加麻烦，使用者可能忽略。
合理性。 使用者认可警示的必要性才会遵守。
与实际使用的匹配。 警示的情形是使用者会遇到的。
「要求的可执行性」值得考虑。 如果警示要求「使用前检查所有紧固件」，而紧固件有几十个且位置隐蔽，实际上使用者不会执行。这种情况下应当简化要求或者改用其他控制措施。
位置与形式的考虑
在产品上的永久标识。 关键信息应当在产品上而非仅在说明书中。
位置的选择。 靠近相关的操作或危险位置。
多处标识。 关键信息可以在多处标注。
说明书中的对应。 产品标识与说明书内容一致。
包装上的标识。 某些信息在包装上有意义。
「关键信息在产品上」的原则很实际。 载重上限、坡度限制、不可乘坐运输这类信息，贴在产品上使用者会看到，写在说明书里可能永远不会被读到。
耐久性的验证
标识要在产品的使用寿命内保持可读：
附着力。 标签不应脱落。
耐磨。 反复摩擦后是否仍清晰。
耐清洁。 清洁剂和消毒剂作用后的状态。
耐候。 光照、温湿度、紫外线的影响。
耐化学。 汗液、体液、日常接触的物质。
验证方法。 按预期的使用条件做老化和磨损试验，之后评价可读性。
「耐清洁」在机构使用的产品上尤其重要，因为频繁的消毒会使标识褪色或脱落。标识在消毒循环后应当仍然清晰，这一项应当验证。
验证的方法
位置检查。 在各种使用状态下（含装了选装件）标识是否可见。
理解测试。 请目标使用者看标识后说明其含义。
任务测试。 观察使用者在操作中是否注意到并遵守标识。
耐久试验。 老化、磨损、清洁循环后的可读性。
专家审阅。 表述的准确性和完整性。
「理解测试」能发现设计者意想不到的问题。 设计者认为清楚的符号或表述，使用者可能完全理解成另一个意思。
标识内容的构成
| 要素 | 内容 |
|---|---|
| 信号词 | 危险、警告、注意的层级 |
| 危险说明 | 什么危险 |
| 后果说明 | 不遵守会怎样 |
| 避免方法 | 应当怎么做 |
| 图形符号 | 通用符号辅助理解 |
四要素齐全的警示才是完整的。 只有信号词和危险说明，缺少后果和避免方法，使用者知道有危险但不知道怎么办。
与风险文件的对应
每个警示标识应当能追溯到风险分析中的某项风险：风险的识别；选择警示作为控制措施的理由（为什么不能用设计或防护解决）；警示的内容与该风险对应；以及警示有效性的验证。
「为什么不用设计解决」这一条在审查中会被问到，因为警示的可靠性低，选择它作为控制措施需要说明理由。
我们的做法
做轮椅检测时，标识的检查是常规项目之一——核对必载信息是否齐全、位置是否符合要求、以及标识本身的耐久性。
耐久性方面，我们建议在环境试验和清洁循环之后复查标识的可读性，因为这两项是标识失效的主要原因，而只检查新品的标识反映不出使用一段时间后的状态。
另外，我们会关注标识的内容与检测数据的一致性——标识上写的载重上限，应当与检测中验证的载荷对应。
如果你需要核对标识的符合性或做标识的耐久验证，可以把产品和标识方案发过来一起讨论，或者直接联系：132 4819 8029。检测能力见服务介绍，产品分类见手动轮椅检测与电动轮椅检测，标准信息见标准查询。
English version
Conclusion. Warning labels are a form of risk control, and among risk controls their reliability is comparatively low, because they depend on the user seeing, understanding and complying. For a warning to work, three conditions must hold together: it must be noticed during the relevant operation; it must be understood, so that the user knows what it says and why; and it must be complied with, meaning the user is willing and able to act on it. Failing any one, the warning provides no risk control. Verifying effectiveness means verifying those three conditions.
The hierarchy of risk control. Control measures differ in reliability. Eliminating the risk by design is the most reliable. Protective measures preventing the hazard structurally are next. Warning information, depending on the user, is the least reliable. Warnings should therefore not be the preferred control, relied upon only where the first two are impracticable or insufficient. A common problem in practice is substituting a warning for something design could solve: where a component can be fitted the wrong way round, the right answer is designing it so that it cannot be, not applying a label saying to note the orientation.
Conditions for being noticed. Position must be within the line of sight during the relevant operation, since a label the user cannot see might as well not exist. Size must suffice to draw attention. Contrast against the background matters. Timing matters, appearing when the user needs the information. Obstruction must be avoided, with the label not covered by other components or accessories in use. And the number must be moderate, since too many labels reduce the attention any one receives. Obstruction is a common real problem: a label on the frame becomes invisible once a cushion or option is fitted. Moderation deserves attention too: a product carrying a dozen warning labels leads users to ignore them all, which is worse than retaining only the few that matter most.
Conditions for being understood. Expression must be clear, stating what the hazard is, what the consequence is and what to do. Language must suit the intended users. Graphical symbols cross language barriers better than text but must be recognised ones. Ambiguity must be avoided, with no room for multiple readings. And information must be complete, since a warning saying only danger, without saying of what or how to avoid it, achieves little. Stating what to do is the part most often omitted: warning that falling may occur helps less than warning that the chair may tip on slopes and stating the maximum gradient, which tells the user what to do.
Conditions for compliance. The required action must be achievable. It must not conflict badly with convenience, since users ignore warnings whose observance is markedly inconvenient. It must seem reasonable, since users comply with warnings they consider necessary. And it must match real use, addressing situations users actually encounter. Achievability deserves thought: a warning to check all fasteners before use, where there are dozens in awkward positions, will not be followed in practice, and the requirement should be simplified or another control adopted.
Position and form. Permanent marking on the product should carry key information rather than leaving it to the instructions. Position should be near the relevant operation or hazard. Repetition is acceptable for key information in several places. Correspondence with the instructions must be maintained. And packaging marking suits certain information. Putting key information on the product is sound practice: weight limits, gradient limits and prohibitions on occupied transport are seen when applied to the product and may never be read in a manual.
Verifying durability. Markings must remain legible across the product's service life. Adhesion must prevent detachment. Abrasion resistance must keep them legible after repeated rubbing. Cleaning resistance covers exposure to cleaning agents and disinfectants. Weathering resistance covers light, temperature, humidity and ultraviolet exposure. Chemical resistance covers perspiration, body fluids and everyday contact. And verification applies ageing and abrasion testing to the expected conditions, assessing legibility afterwards. Cleaning resistance matters particularly for institutional products, where frequent disinfection fades or lifts markings. Markings should remain legible after disinfection cycling, and this should be verified.
Assessment methods. Position checking confirms visibility in every state of use, including with options fitted. Comprehension testing asks target users to explain what a marking means. Task testing observes whether users notice and comply during operation. Durability testing assesses legibility after ageing, abrasion and cleaning cycles. And expert review addresses accuracy and completeness of wording. Comprehension testing reveals problems designers do not anticipate: a symbol or phrase the designer considers clear may be understood as something else entirely.
How we handle it. In wheelchair testing, marking inspection is a routine item, covering whether required information is complete, whether positions meet requirements and whether markings themselves are durable. On durability we suggest re-checking legibility after environmental testing and cleaning cycles, since those are the principal causes of marking failure and inspecting new-product markings alone says nothing about their state after a period in use. We also attend to consistency between marking content and test data: the weight limit on the label should correspond to the load verified in testing.
Send us the product and marking scheme and we will work through compliance and durability verification. Phone or WeChat: +86 132 4819 8029.