Permit Required Confined Space 持证限闭空间

Confined spaces can be categorized generally as those with open tops and with a depth that will restrict the natural movement of air, and enclosed spaces with very limited openings for entry. In either of these cases, the space may contain mechanical equipment with moving parts. Any combination of these parameters will change the nature of the hazards encountered.

限闭空间一般可以分为顶部开口、内有深度、空气自然流动受到限制的封闭空间；或是仅有非常有限出入口的封闭空间。在这两种情况下，空间内都可能有带运动部件的机械设备。这些因素叠加将改变可能遇到的危害的性质。

 

89% of confined space fatalities occurred with jobs authorized by supervisors, and 80% of fatalities happened in locations that had been previously entered by the same person who later died.

89％的限闭空间死亡事件发生在有主管授权的作业中，80％的死亡事件发生在以前同一人员曾经进入过的位置，后来不幸就降临了。

 

Confined spaces are enclosed or partially enclosed spaces of a size such that a worker can squeeze entry for performing assigned work through a narrow opening - they’re tough to get in and out of, tight spaces. These spaces are normally only entered to perform specific tasks and then barricaded to prevent unauthorized access.

限闭空间全部或部分是被封闭的，其空间大小仅容许工人通过狭窄的开口挤入，进行被派发的工作 - 他们很难进出狭窄的空间。这些空间通常只能进入执行特定的工作，然后关闭以防止未经授权的出入。

 

Examples include storage tanks or bins, mixing tanks, rail road tank cars, silos, vaults, and pits. Think of any large tank used for holding liquid. Sometimes, these big storage containers need to be cleaned out, so you send a worker to get inside and they’re completely surrounded by walls of the structure, with only a small entry/exit hatch for escape if things go awry. Confined spaces create the ideal conditions for the onset of claustrophobia. Confined spaces can be large or small and above or below ground.

实例包括储罐或箱罐，搅拌罐，铁路或道路罐车，筒仓，沉仓和沉坑。想象一下任何用于储存液体的大罐子。有时，这些大型储罐容器需要清理干净，所以你交派一个员工进入内部，并且完全被结构四壁包围；如果事情跑偏，只有一个小的出入盖口可以脱身。密闭空间为幽闭恐惧症创造了理想的发病条件。密闭空间有大有小，可高于或低于地面。

 

By their very nature and configuration, many confined spaces may foster a hazardous atmosphere. These are normally poorly ventilated areas, so the release of vapors which might otherwise be released into the open air can create an oxygen-deficient, toxic, combustible, or otherwise harmful atmosphere. Confined spaces kill when several unexpected situations develop. Exposure to these atmospheres can result in immediate asphyxiation, acute or chronic poisoning, or impairment that can result in injury.

由于其性质和构成，大部分限闭空间会滋生有害气氛。这些地方通常通风不畅，因此本可释放到露天空气中的蒸气泄放于此，从而产生缺氧，有毒，易燃或有其它危害的气氛。若干意想不到的情况一旦发生，限闭空间即可致命。接触这类气氛可导致立即窒息，急性或慢性中毒或可能导致受伤等伤害。

 

Degreasers, pits, and certain types of storage tanks may be classified as open topped confined spaces that usually contain no moving parts. However, gases that are heavier than air (butane, propane, and other hydrocarbons) remain in depressions and will flow to low points where they are difficult to remove. Open topped water tanks that appear harmless may develop toxic atmospheres such as hydrogen sulfide from the vaporization of contaminated water. Therefore, these gases (heavier than air) are a primary concern when entry into such a confined space is being planned. Other hazards may develop due to the work performed in the confined space or because of corrosive residues that accelerate the decomposition of scaffolding supports and electrical components.

沉淀池，沉坑和某些类型的储罐可以归为通常不带活动部件的顶部敞开型限闭空间。然而，比空气重的气体(丁烷，丙烷和其他碳氢化合物)会滞留在凹坑中，并且将流聚到难以排出的低点。貌似无害的开放式水箱可能会从污染水的挥发物中产生毒性气体，如硫化氢。因此，这些气体（比空气重）是计划进入这类限闭空间时的主要隐忧。限闭空间中进行作业或引起支撑结构和电气部件加速分解的腐蚀性残留物还会产生其它危害。

 

Confined spaces such as sewers, casings, tanks, silos, vaults, and compartments of ships usually have limited access. The problems arising in these areas are similar to those that occur in open topped confined spaces. However, the limited access increases the risk of injury. Gases which are heavier than air such as carbon dioxide and propane, may lie in a tank or vault for hours or even days after the containers have been opened. Because some gases are odorless, the hazard may be overlooked with fatal results. Gases that are lighter then air may also be trapped within an enclosed type confined space, especially those with access from the bottom or side.

限闭空间如下水道，箱体，储罐，筒仓，沉仓和船舶舱室通常也是进出受限的。这些区域出现的问题与在开放式限闭空间中发生的问题相似。并且，进出受限增加了受伤的风险。比空气重的气体，例如二氧化碳和丙烷，可能会在容器空间打开后几个小时甚至几天内滞留在储罐或沉仓中。一些气体因为是无味的，所以危害可能会被忽视，而带来致命的后果。比空气轻的气体也可能被封闭在封闭式限闭空间内，特别是从底部或侧面进入的气体。

 

Hazards specific to a confined space are dictated by: (1) the material stored or used in the confined space; as an example, damp activated carbon in a filtration tank will absorb oxygen, thus creating an oxygen deficient atmosphere; (2) the activity carried out, such as the fermentation of molasses that creates ethyl alcohol vapors and decreases the oxygen content of the atmosphere; or (3) the external environment, as in the case of sewer systems that may be affected by high tides, heavier than air gases, or flash floods.

限闭空间特定的危害取决于以下方面：（1）限闭空间中储存或使用的物料; 比如，过滤罐中潮湿的活性炭会吸收氧气，从而产生缺氧气氛; （2）限闭空间中所进行的活动，比如糖蜜发酵产生乙醇挥发气，并降低气氛中的氧含量; 以及（3）外部环境，如下水道可能受高潮汐，重于空气的气体，或溢洪等因素的影响。

 

The most hazardous kind of confined space is the type that combines limited access and mechanical devices. All the hazards of open top and limited access confined spaces may be present together with the additional hazard of moving parts. Digesters and boilers usually contain power-driven equipment which, unless properly isolated, may be inadvertently activated after entry. Such equipment may also contain physical hazards that further complicate the work environment and the entry and exit process.

最危险的限闭空间是进出受限并带有机械设备的类型。顶部敞开型和进出受限型限闭空间的各种危害可能与运动部件的额外危险叠加存在。搅拌器和锅炉常带有动力驱动设备，除非阻断得当，否则可能在进入后无意中启动。这类设备还可能隐藏着使工作环境和进出过程进一步复杂化的物理危害。

 

Reasons for Entering Confined Spaces

Entering a confined space as part of the industrial activity may be done for various reasons. It is done usually to perform a necessary function, such as inspection, repair, maintenance (cleaning or painting), or similar operations which would be an infrequent or irregular function of the total industrial activity.

进出限闭空间是工厂作业的组成部分，可能出于各种原因。通常是为执行必要的职能，如检查，维修，维护（清洁或涂漆）或类似的作业，一般是整个工厂作业中不常用或不规律的职能。

 

Entry may also be made during new construction. Potential hazards should be easier to recognize during construction since the confined space has not been used. The types of hazards involved will be limited by the specific work practices. When the area meets the criteria for a confined space, all ventilation and other requirements should be enforced.

项目新建期间也可能进出限闭空间。由于限闭空间未被使用，潜在的危害在施工中应该更容易识别。 所涉及的危害类型将受到具体工作实践的限制。 当该区域满足限闭空间的条件时，应执行所有通风和其它要求。

 

One of the most difficult entries to control is that of unauthorized entry, especially when there are large numbers of workers and trades involved, such as welders, painters, electricians, and safety monitors.

最难控制的活动之一是未经批准进出限闭空间，特别是当涉及到大量工人和工种时，例如焊工，油漆工，电工和安全员等。

 

A final and most important reason for entry would be emergency rescue. This, and all other reasons for entry, must be well planned before initial entry is made and the hazards must be thoroughly reviewed. The standby person and all rescue personnel should be aware of the structural design of the space, emergency exit procedures, and life support systems required.

进出限闭空间最后的，也是最重要的原因是应急救援。这一原因和所有其它进出限闭空间的原因一样，必须在初步进入之前进行良好的计划，并且必须对危害性彻底审核。后备人员和所有救援人员应了解空间内部的结构设计，紧急逃生程序和所需的生命支持系统。

 

Asphyxiation is the leading cause of death in confined spaces.

窒息是限闭空间中死亡事故的主要原因。

Oxygen deficiency is one probable factor contributing to confined space accidents. This is when the air in a confined space is consumed by chemical or biological reactions, diluting the percentage of oxygen in the immediate atmosphere to below 21%, causing increasingly negative physiological responses as that percentage declines.

缺氧是导致限闭空间事故的一个潜在因素。当化学或生物反应消耗限闭空间空气，周围气氛中的氧气百分比被稀释到21％以下，并随着其持续下降，造成生物反应越来越反常。

 

 

 

 

Oxygen displacement is another killer in confined spaces. Typically, this is when inert gas is present at levels that remove oxygen from the chamber, essentially crowding out the normal air we breathe and replacing it with, say colorless, odorless gases like nitrogen or carbon dioxide, creating a situation of complete suffocation for workers.

驱氧是限闭空间的另一个杀手。特别是当惰性气体存在含量达到可以从腔室中驱除氧气的水平时，基本上挤出我们呼吸的正常空气并使其转换为无色，无味的气体，如氮气或二氧化碳，从而造成工人完全窒息的险情。

 

Other common, problem situations in confined spaces involve flammable atmospheres, toxic gases and solvents, each posing different, specific hazards that have killed high-risk workers in the past.

限闭空间中的其它常见隐患情况包括易燃环境，有毒气体和溶剂等，每种都带有不同的特定危害，并在过往造成过高危人员致死的教训。

 

HAZARDOUS ATMOSPHERES 有害气氛

Hazardous atmospheres encountered in confined spaces can be divided into four distinct categories: Flammable, Toxic, Irritant and/or Corrosive, and Asphyxiating.

限闭空间常遇的危险气氛可分为四类：易燃，有毒，刺激性和/或腐蚀性，以及窒息性。

 

Flammable Atmospheres 可燃气氛

A flammable atmosphere generally arises from enriched oxygen atmospheres, vaporization of flammable liquids, byproducts of work, chemical reactions, concentrations of combustible dusts, and desorption of chemical from inner surfaces of the confined space.

可燃气氛通常来自富氧气氛，易燃液体挥发，作业副产物，化学反应，可燃粉尘积聚和化学物质从限闭空间内表面脱附。

 

An atmosphere becomes flammable when the ratio of oxygen to combustible material in the air is neither too rich nor too lean for combustion to occur. Combustible gases or vapors will accumulate when there is inadequate ventilation in areas such as a confined space. Flammable gases such as acetylene, butane, propane, hydrogen, methane, natural or manufactured gases or vapors from liquid hydrocarbons can be trapped in confined spaces, and since many gases are heavier than air, they will seek lower levels as in pits, sewers, and various types of storage tanks and vessels. In a closed top tank, it should also be noted that lighter than air gases may rise and develop a flammable concentration if trapped above the opening.

当空气中的氧气与可燃物料的比例既不太浓也不太稀足以发生燃烧时，气氛就变为易燃。 当限闭空间等区域的通风不足时，可燃气体或蒸气将积聚。易燃气体如乙炔，丁烷，丙烷，氢气，甲烷，天然或人造的气体或液体烃类的蒸气可能滞留在限闭空间内，由于许多气体比空气重，因此它们将流向较低的位置，如沉坑，下水道，和各种类型的储罐和容器。顶部封闭罐中，还应注意，比空气更轻的气体如果滞留于出入孔上方，可能积聚并达到易燃浓度。

 

The byproducts of work procedures can generate flammable or explosive conditions within a confined space. Specific kinds of work such as spray painting can result in the release of explosive gases or vapors. Welding in a confined space is a major cause of explosions in areas that contain combustible gas.

作业流程副产品可在限闭空间内产生易燃或爆炸性的条件。喷涂等特定工作可能导致爆炸性气体或挥发物释放。限闭空间内焊接是含可燃气体区域爆炸的主要原因。

 

 

Chemical reactions forming flammable atmospheres occur when surfaces are initially exposed to the atmosphere, or when chemicals combine to form flammable gases. This condition arises when dilute sulfuric acid reacts with iron to form hydrogen or when calcium carbide makes contact with water to form acetylene. Other examples of spontaneous chemical reactions that may produce explosions from small amounts of unstable compounds are acetylene-metal compounds, peroxides, and nitrates. In a dry state, these compounds have the potential to explode upon percussion or exposure to increased temperature. Another class of chemical reactions that form flammable atmospheres arise from deposits of pyrophoric substances (carbon, ferrous oxide, ferrous sulfate, iron, etc.) that can be found in tanks used by the chemical and petroleum industry. These tanks containing flammable deposits will spontaneously ignite upon exposure to air.

化学物料表面一经接触大气，或相互结合形成易燃气体时，会经由化学反应而形成易燃气氛。 当稀硫酸与铁反应形成氢时，或当碳化钙与水接触形成乙炔时，就会出现这种情况。由少量不稳定化合物产生爆炸性的自发化学反应的其它例子包括乙炔 - 金属化合物，过氧化物和硝酸盐。在干燥状态下，这些化合物可能会在敲击或接触升高的温度下爆炸。形成易燃气氛的另一类化学反应来自化学和石油工业所使用的储罐中常见的自燃物质(碳，氧化亚铁，硫酸亚铁，铁等)的沉积物。包含易燃沉积物的这些储罐在暴露于空气时会自燃。

 

Combustible dust concentrations are usually found during the process of loading, unloading, and conveying grain products, nitrated fertilizers, finely ground chemical products, and any other combustible material. High charges of static electricity, which rapidly accumulate during periods of relatively low humidity (below 50%), can cause certain substances to accumulate electrostatic charges of sufficient energy to produce sparks and ignite a flammable atmosphere. These sparks may also cause explosions when the right air or oxygen to dust or gas mixture is present.

可燃粉尘积聚通常可见于装卸和输送谷物，硝化肥料，细磨的化学制品和任何其他可燃材料的作业中。在相对较低的湿度(低于50％)期间迅速积聚的高电量静电可能导致某些物质积聚足够能量的静电电荷，产生火花并点燃易燃气氛。当存在合适的空气或氧气与灰尘或气体混合物时，这类火花也可能引起爆炸。

 

Toxic Atmospheres毒性气氛

The substances to be regarded as toxic in a confined space can cover the entire spectrum of gases, vapors, and finely-divided airborne dust in industry. The sources of toxic atmospheres encountered may arise from the following:

限闭空间中视为毒性的物料可以涵盖业界所有气体，挥发物和气溶细尘。常见有毒气体的来源可能来自于：

1. The manufacturing process (for example, in producing polyvinyl chloride, hydrogen chloride is used as will as vinyl chloride monomer, which is carcinogenic).
2. The product stored [removing decomposed organic material from a tank can liberate toxic substances, such as hydrogen sulfide (H2S)].
3. The operation performed in the confined space (for example, welding or brazing with metals capable of producing toxic fumes).
1.生产流程 (例如，在生产聚氯乙烯时，氯化氢与氯乙烯单体同时使用，氯乙烯是致癌物)。

2.储存的物料 [从储罐中清除分解的有机物会释放有毒物质，如硫化氢(H₂S)]。

3.限闭空间中进行的作业 (例如，用能够产生有毒烟雾的金属进行焊接或钎焊)。

 

 

 

During loading, unloading, formulation, and production, mechanical and/or human error may also produce toxic gases which are not part of the planned operation.

在装载，卸载，配制和生产过程中，机械和/或人为错误也可能产生作业范围外的有毒气体。

 

Carbon monoxide (CO) is a hazardous gas that may build up in a confined space. This odorless, colorless gas that has approximately the same density as air is formed from incomplete combustion of organic materials such as wood, coal, gas, oil, and gasoline; it can be formed from microbial decomposition of organic matter in sewers, silos, and fermentation tanks. Carbon monoxide is an insidious toxic gas because of its poor warning properties. Early stages of CO intoxication are nausea and headache. Carbon monoxide may be fatal at 1000 ppm in air, and is considered dangerous at 200 ppm, because it forms carboxyhemoglobin in the blood which prevents the distribution of oxygen in the body.

一氧化碳（CO）是可能在限闭空间积聚的有害气体。 这种与空气大致相同密度的无臭无色气体是由有机材料如木材，煤，气，油和汽油的不完全燃烧形成的。 它可以由下水道，筒仓和发酵罐中有机物的微生物分解形成。 一氧化碳是一种阴险的有毒气体，因为其预警性差。CO中毒在早期阶段表现为恶心和头痛。 一氧化碳在空气中达1000ppm即可致命，而在200ppm时即形成危险，因为它在血液中形成碳氧血红蛋白，能阻止氧在体内传布。

 

Carbon monoxide is a relatively abundant colorless, odorless gas, therefore, any untested atmosphere must be suspect. It must also be noted that a safe reading on a combustible gas indicator does not ensure that CO is not present. Carbon monoxide must be tested for specifically. The formation of CO may result from chemical reactions or work activities, therefore fatalities due to CO poisoning are not confined to any particular industry. There have been fatal accidents in sewage treatment plants due to decomposition products and lack of ventilation in confined spaces. Another area where CO results as a product of decomposition is in the formation of silo gas in grain storage elevators. In another area, the paint industry, varnish is manufactured by introducing the various ingredients into a kettle, and heating them in an inert atmosphere, usually town gas, which is a mixture of carbon dioxide and nitrogen.

一氧化碳是一种相对常见的无色无味气体，因此，任何未经测试的环境气氛都必须存疑。 还必须注意的是，可燃气体指示器上的安全读数不能确保CO不存在。必须特别测试一氧化碳。 CO的形成可能由化学反应或作业活动引起，因此由于CO中毒而导致的死亡并不局限于任何特定行业。污水处理厂由于产物分解和限闭空间缺乏通风而发生伤亡事故。 CO作为分解产物的另一个区域是谷物储仓电梯中形成的筒仓气体。在另一个领域，涂料工业的清漆是通过将各种成分导入釜中而生产，并在惰性气氛中加热的，通常是混合二氧化碳和氮气的民用煤气。

 

In welding operations, oxides of nitrogen and ozone are gases of major toxicologic importance, and incomplete oxidation may occur and carbon monoxide can form as a byproduct.

焊接作业中，氮和臭氧的氧化物是主要毒性气体，并且可能发生不完全的氧化，一氧化碳会作为副产物而产生。

 

Another poor work practice, which has led to fatalities, is the recirculation of diesel exhaust emissions. Increased CO levels can be prevented by strict control of the ventilation and the use of catalytic convertors..

导致死亡的另一种不良作业操作是柴油机废气排放再循环。通过严格控制通风和使用催化转化器可以防止CO含量升高。

 

Irritant (Corrosive) Atmospheres刺激性（腐蚀性）气氛

Irritant or corrosive atmospheres can be divided into primary and secondary groups. The primary irritants exert no systemic toxic effects (effects on the entire body). Examples of primary irritants are chlorine, ozone, hydrochloric acid, hydrofluoric acid, sulfuric acid, nitrogen dioxide, ammonia, and sulfur dioxide. A secondary irritant is one that may produce systemic toxic effects in addition to surface irritation. Examples of secondary irritants include benzene, carbon tetrachloride, ethyl chloride, trichloroethane, trichloroethylene, and chloropropene.

刺激性或腐蚀性气体可分为初级和二级组。初级刺激物不产生全身毒性作用 (对整个身体的影响)。初级刺激物的实例是氯，臭氧，盐酸，氢氟酸，硫酸，二氧化氮，氨和二氧化硫。二级刺激物除了表面刺激外，还可能产生全身毒性作用。二级刺激物的实例包括苯，四氯化碳，氯乙烷，三氯乙烷，三氯乙烯和氯丙烯等。

 

Irritant gases vary widely among all areas of industrial activity. They can be found in plastics plants, chemical plants, the petroleum industry, tanneries, refrigeration industries, paint manufacturing, and mining operations.

各种工业活动领域的刺激性气体差别很大。它们可以在塑料工厂，化工厂，石油工业，制革厂，制冷行业，油漆制造和采矿作业中都很常见。

 

Prolonged exposure at irritant or corrosive concentrations in a confined space may produce little or no evidence of irritation. This may result in a general weakening of the defense reflexes from changes in sensitivity. The danger in this situation is that the worker is usually not aware of any increase in his/her exposure to toxic substances.

在限闭空间内长时间暴露于刺激性或腐蚀性浓度下可能显现很少或没有刺激的迹象。 这可能导致防御反射由于敏感度变化而大幅削弱。这种情况的危险在于工人通常不会意识到他/她接触有毒物质的状况有所增加。

 

Asphyxiating Atmospheres 窒息性气氛

The normal atmosphere is composed approximately of 20.9% oxygen and 78.1% nitrogen, and 1% argon with small amounts of various other gases. Reduction of oxygen in a confined space may be the result of either consumption or displacement.

正常空气气氛大约由20.9％的氧气和78.1％的氮气，1％的氩气与少量各种其他气体组成。 限闭空间中的氧气减少会因为其被消耗或驱排而形成。

 

The consumption of oxygen takes place during combustion of flammable substances, as in welding, heating, cutting, and brazing. A more subtle consumption of oxygen occurs during bacterial action, as in the fermentation process. Oxygen may also be consumed during chemical reactions as in the formation of rust on the exposed surface of the confined space (iron oxide). The number of people working in a confined space and the amount of their physical activity will also influence the oxygen consumption rate.

氧气的消耗在易燃物质的燃烧过程中发生，如在焊接，加热，切割和钎焊中。 在细菌作用过程中会发生更微细的氧气消耗，比如在发酵过程中。在化学反应期间，氧气也可能被消耗，就像在限闭空间 (氧化铁) 的裸露表面上形成锈。限闭空间工作人数和身体活动量也会影响氧气消耗率。

 

A second factor in oxygen deficiency is displacement by another gas. Examples of gases that are used to displace air, and therefore reduce the oxygen level are helium, argon, and nitrogen. Carbon dioxide may also be used to displace air and can occur naturally in sewers, storage bins, wells, tunnels, wine vats, and grain elevators. Aside from the natural development of these gases, or their use in the chemical process, certain gases are also used as inerting agents to displace flammable substances and retard pyrophoric reactions. Gases such as nitrogen, argon, helium, and carbon dioxide, are frequently referred to as non-toxic inert gases but have claimed many lives. The use of nitrogen to inert a confined space has claimed more lives than carbon dioxide. The total displacement of oxygen by nitrogen will cause immediate collapse and death. Carbon dioxide and argon, with specific gravities greater than air, may lie in a tank or manhole for hours or days after opening. Since these gases are colorless and odorless, they pose an immediate hazard to health unless appropriate oxygen measurements and ventilation are adequately carried out.

缺氧的第二个诱因是另一种气体对其驱排。其它气体驱排空气，造成降低氧气含量的例子包括氦气，氩气和氮气。二氧化碳也会造成空气驱排，并且可以在下水道，储存箱，井道，隧道，葡萄酒桶和粮食提升机中自然发生。这些气体除了自然积聚或在化学过程中使用外，某些也被用作惰性剂以驱排易燃物质并延缓自燃反应。诸如氮气，氩气，氦气和二氧化碳等气体通常被称为无毒惰性气体，但是已经夺走了许多生命。使用氮气对限闭空间惰性化比使用二氧化碳夺走更多人命。氮气对氧气的彻底驱排会造成即时崩溃和死亡。比重大于空气的二氧化碳和氩气可能在储罐或人孔开启后几个小时或几天内仍滞留其间。由于这些气体是无色无味的，因此如果不充分进行恰当的氧气测量和通风，会对健康构成直接危害。

 

Oxygen deprivation is one form of asphyxiation. While it is desirable to maintain the atmospheric oxygen level at 21% by volume, the body can tolerate deviation from this ideal. When the oxygen level falls to 17%, the first sign of hypoxia is a deterioration to night vision which is not noticeable until a normal oxygen concentration is restored. Physiologic effects are increased breathing volume and accelerated heartbeat. Between 14-16% physiologic effects are increased breathing volume, accelerated heartbeat, very poor muscular coordination, rapid fatigue, and intermittent respiration. Between 6-10% the effects are nausea, vomiting, inability to perform, and unconsciousness. Less than 6%, spasmatic breathing, convulsive movements, and death in minutes.

氧气驱排是造成窒息的一种形式。虽然希望将大气氧气水平保持在21％(体积)，但身体可以容忍偏离该理想值。当氧气含量下降到17％时，缺氧的第一个征兆是夜视能力下降，只有恢复正常氧浓度才接近正常的。生理作用是呼吸量增加、心跳加快。14-16％时的生理反应是呼吸量增加，心跳加快，肌肉协调非常差，快速疲劳和间歇性呼吸。6-10％的反应是恶心，呕吐，丧失执行能力，无意识。少于6％，挥发性呼吸，惊厥动作，几分钟内死亡。

 

A permit-required confined space is an area which:

• Contains or has the potential to contain a hazardous atmosphere
• Contains a material with the potential to engulf someone who enters the space
• Has an internal configuration that might cause an entrant to be trapped or asphyxiated
• Contains any other recognized serious safety or health hazards

要求作业许可的限闭空间包括：

•含有或有可能含有危害气体的

•含有潜在吞噬进入该空间人员的物质的

•内部配置可能会导致进入者被困或窒息的

•包含任何其它已辨识的严重安全或健康危害的

 

Your company’s Permit-required Confined Space Entry Program is its overall policy and plan for protecting you and other employees and contractors against confined space hazards, and for regulating entry into its permit-required spaces. Before you may enter a permit space, your supervisor and/or the attendant must take any measures necessary to isolate the permit space and eliminate or control hazards. These measures include lockout or tagging of equipment to ensure that it does not present a hazard.

您公司的限闭空间持证进出规程是保护您和其他员工和承包商免受限闭空间危害并规范限闭空间持证进出作业的总规章和预案。在您进入持证空间之前，您的主管和/或后援必须采取必要措施来隔离持证空间并消除或控制危害。这些措施包括设备锁闭和标识，以确保其不会造成危害。

Measures also include testing and monitoring the air for contaminants and adequate oxygen, as well as purging, ventilating, and flushing unsafe atmospheres or chemicals from the space. If a permit space requires forced air ventilation, the ventilator must eliminate or reduce hazardous atmospheric conditions to within acceptable limits, employing PPE as necessary to accomplish this, and maintain a safe atmosphere until the work is completed and personnel have left the space. Before you may enter a permit space, your supervisor and/or the attendant must test the internal atmosphere of the space with calibrated, direct-reading instruments.

其它措施还包括测试和监测空气中污染物和合适的氧气含量，以及空间气消，通风和洗消不安全的环境或化学物质。如果持证空间需要强制通风，排风机必须将危害气氛环境条件消除或减少到可接受的限度内，并采用必要的PPE来达到此目的，以保持安全氛围，直到工作完成、人员离开该空间。在您进入持证空间前，您的主管和/或后援必须使用校准的直读仪器测试该空间的内部空气。

OSHA requires that your employer provide any necessary equipment at no cost to you to ensure your safe entry and exit of the permit space. Equipment includes ventilation, testing and monitoring instruments to maintain an acceptable atmosphere quality. Equipment may also include communication devices to monitor your status and provide evacuation alerts, any personal protective equipment necessary for adequate protection, and appropriate lighting to enter, work, and exit safely. Your employer must also provide barriers or shields to protect you from external hazards, such as electrical hazards or sources of extreme heat and cold, ladders or other equipment for safe entrance and exit, and all rescue and emergency equipment for rescuing entrants.

OSHA要求您的雇主为您免费提供任何必要的设备，以确保您安全进入和离开持证空间。 设备包括通风，测试和监测仪器，以保持可接受的现场空气质量。设备还可以包括监控您的状态的通信设备，并提供疏散警报，必要的个人防护装备，以及适当的照明用以进入，工作和出离的安全。您的雇主还必须提供屏障或防护，以保护您免受外部危害，例如电气危害或极端寒冷等外部危险，比如梯子或其它用于安全出入的设备，以及拯救进入者的所有救援和应急设备。

Employers must ensure that employees working directly in a permit space perform specific duties, in addition to knowing the hazards and symptoms of exposure.

雇主必须确保直接在持证空间中工作的雇员除了了解接触危害和症状外，执行特定的职责。