By the American safety experts K.J. Graham and K.F. Kinney put forward by the operating conditions hazard evaluation method is a simple and easy to implement to measure people in a potentially hazardo

By the American safety experts K.J. Graham and K.F. Kinney put forward by the operating conditions hazard evaluation method is a simple and easy to implement to measure people in a potentially hazardous... LEC Method Introduction LEC (Operating Conditions Hazard Analysis Method), proposed by American safety experts K.J. Graham and K.F. Kinney, is a semi-quantitative safety evaluation method for the sources of hazards in potentially hazardous operating environments, which is used for evaluating the dangers and hazards of the operators' work in potentially hazardous environments.

The method evaluates the size of the risk of operator injury and death by the product of the indicator values of three factors related to the system risk, which are:

L (likelihood, the possibility of accidents)

E (exposure, the frequency of exposure of personnel to hazardous environments)

C (consequence, once an accident occurs)

C (risk), which is a semi-quantitative safety evaluation method for evaluating the risk of injury and death of the operator when working in potentially hazardous environments. CONSEQUENCE, the possible consequences if an accident occurs).

The different levels of the three factors are assigned different scores, and then the product of the three scores, D (danger, danger) to evaluate the magnitude of the danger of the operating conditions.

That is: D = L × E × C

The greater the value of D, the greater the danger of the system, the need to increase safety measures, or to change the likelihood of accidents, or to reduce the human body exposed to the hazardous environment in the frequency of accidents or reduce the loss of accidents until adjusted to the permissible range.

LEC method of assigning points

L-Likelihood of an accident

Likelihood of an accident

Score value

Totally predictable

10

Quite likely

6

Likely, but infrequent

3

Little likely, completely unexpected

1

Likely, conceivable

0.5

Extremely unlikely

0.2

Practically impossible

0.1

E-Exposure of human body to this hazardous environment Frequency of exposure to the hazardous environment

Frequency of exposure to the hazardous environment

Score value

Continuous exposure

10

Exposure during working hours every day

6

Weekly, or occasional exposure

3

Monthly exposure

2

exposed several times a year

1

very rarely exposed

0.5

C-Consequences of an accident

Consequences of an accident

fraction

catastrophe, many deaths

100

catastrophe Several deaths

40

Very serious, one person killed

15

Serious, seriously injured

7

Major, disabling

3

Compelling, requires ambulance

1

Hazard Score D = LEC

Score Value

Hazard Score

Score Value

Score Value

Score Value

Score Value

Score Value

Score Value

Score Value

Score Value /p>

Level of Hazard

>320

>320

>320

>320

Highly Hazardous, Needs Immediate Rectification

>320

Significantly Dangerous, Needs Rectification

>320

20>320

Possibly Dangerous, Needs Attention

>20

Slightly dangerous, perhaps acceptable

LEC Method Advantages and Disadvantages

AdvantagesOperating Conditions Hazard Evaluation Method evaluates the degree of danger of people working in a potentially dangerous operating environment, the method is simple and easy to implement, the level of danger is divided into more clear and eye-catching.

Disadvantages Because it is mainly based on experience to determine the score of the three factors and the classification of the degree of risk, it has certain limitations. In addition, the evaluation method can be appropriately modified according to one's own experience and specific situation in the specific application.

The LEC method is applied to a polyester chemical fiber plant in the production of staple fibers, there is a component cleaning process, in order to evaluate the risk of this operating condition, please determine the score value of each factor.

1. Likelihood of accidents (L): component cleaning used in triethylene glycol, is a class IV flammable liquid, such as heating to the boiling point, the vapor explosion limit range of 0.9-9.2%, is a class I flammable vapors. Component cleaning, triethylene glycol need to be heated and then used, resulting in triethylene glycol vapors can easily spread the space, such as poor indoor ventilation, has a certain potential danger, is "possible, but infrequent", the score value of the L = 3.

2. Exposure to hazardous environments of the frequency of (E): Cleaning personnel every day in the environment, take the E = 1.0%.

3. Consequences of accidents (C): If a combustion and explosion accidents, the consequences will be very serious, may cause deaths and injuries, take C = 15.

Therefore, the hazard score D = LEC = 3 × 6 × 15 = 270

270 in the 160-320 range, the hazard level is "between". Between 160-320, the danger level is "highly dangerous, need immediate rectification" category.