7.1.2 Safety Belt
1.Basic Structure and Function of Safety Belt
(1)Basic structure
As shown in Fig.7-4,the full-body safety belt consists of a belt,a rope and metal accessories.According to the nature of the work,its structural form is also different,mainly including two kinds of safety belts:pole work safety belts and hanging work safety belts,etc.
Fig.7-4 Parts of Full-Body Safety Belt
Safety belts are made of nylon,vinylon,silk and other materials.However,due to the small amount of raw materials and high cost of silk,chinlon is currently the main material.Ordinary carbon steel or aluminum alloy steel for metal accessories.
(2)Basic function
Safety belts are protective articles for high-altitude workers to prevent falling casualties.It is widely used in the construction,installation and maintenance of overhead transmission and distribution line towers.In order to prevent workers from falling from high places,safety belts must be used.The safety belt for pole-enclosing operation is mainly used for line maintenance and patrol operation;Hanging safety belts are mainly used in construction,installation and other operations.Fig.7-5 shows the structures of two kinds of safety belts,i.e.pole work safety belts and hanging work safety belts,and Fig.7-6 shows the picture of three-point and five-point safety belts.
Fig.7-5 Structure of Safety Belt
(a)Pole work safety belt;(b)Hanging work safety belt
Fig.7-6 Safety Belts
(a)Five-point safety belt;(b)Three-point safety belt
2.Classification and Technical Specifications of Safety Belt
(1)Classification
①Safety belts can be divided into three categories according to the use conditions,i.e.pole work safety belts,zone limiting safety belts and falling hanging safety belts,as shown in Table 7-2.
Table 7-2 Classification of Safety Belts According to Use Conditions
Table(Cont'd)
②Safety belts can be divided into three categories according to different structural forms,as shown in Table 7-3.
Table 7-3 Classification of Safety Belts by Structure
(2)Technical specifications
①The main belt must be a whole piece with a width of not less than 40mm and a length of 1300-1600 mm.
②The waistband is with a width of not less than 80mm,a length of 600-700 mm,and an auxiliary belt width of not less than 20mm.(https://www.daowen.com)
③The effective length of safety rope(including unexpanded buffer)shall not be greater than 2m,and buffer or falling protector shall be additionally installed for special needs exceeding 2m.When working at high altitude with a range of activities exceeding the protection range of safety rope,it must be used in conjunction with speed differential automatic controller.For safety belts with two safety belts(including unexpanded bumper),the single effective length shall not be more than 1.2m.
3.Safety Belt Inspection Contents
(1)Before use,the safety belt must be visually inspected.If it is found to be damaged,deteriorated or metal accessories are broken,it shall be forbidden for use.When not in use at ordinary times,it shall also be visually inspected once a month.
(2)Before using the safety belt,it is necessary to check whether the test certificate is within the valid period.Safety belts exceeding the valid test cycle cannot be used.
(3)Before using the safety belt,a force impulse test must be carried out to check the bearing capacity of the safety belt,as shown in Fig.7-7.
Fig.7-7 Safety Belt Impulse Test
4.Usage of Safety Belt
(1)The safety belt shall be hung at a high place and used at a low place or fastened horizontally.The high hanging and low use is to hang the rope of the safety belt at a high place,and the operator works below the hanging point;the horizontal fastening is to tie the safety belt at the waist when the single belt is used,and the hook of the rope is hung at the same level as the safety belt.The worker shall keep a distance from the hook that approximately equals to the length of the rope.Low hanging and high use is prohibited,and the live beam clamp shall be fastened tightly.
(2)When using the safety belt in low temperature environment,care shall be taken to prevent the safety belt from hardening and splitting.
(3)The frequently used safety rope shall be subject to regular appearance inspection.In case of abnormality,new rope shall be replaced in time,and attention shall be paid to the problem of adding rope slings.
(4)The safety belt cannot be knotted to prevent the safety rope from being disconnected from the knotted place in case of impact.The safety hook shall be hung on the connecting ring instead of directly hanging on the safety rope to prevent the safety rope from being cut off in case of falling.
(5)The various parts on the safety belt shall not be arbitrarily removed.When replacing the new rope,pay attention to the use of a noose.The belt can be used for 3 to 5 years.If the abnormality is found,it shall be scrapped in advance.
(6)When using and storing the safety belt,avoid contact with high temperature,open flames and acids,as well as hard objects with acute angles and chemicals.
Fig.7-8 shows the wearing method of the safety belt,and Fig.7-9 shows the using method of the safety belt when working on the rod.
Fig.7-8 Wearing Method of Safety Belt
Fig.7-9 Use of Work Safety Belt on Rod
5.Storage of Safety Belts
(1)Safety belts shall be stored in a dry and ventilated environment,numbered and fixed on shelves.They shall not be exposed to high temperature,open flames,strong acids,strong alkalis and sharp hard objects,and shall not be exposed to the sunlight.Tools with hooks and thorns shall not be used when moving,and shall be protected from sunlight and rain during transportation.
(2)Safety belts shall be kept clean regularly.They can be put into warm water and gently rubbed with soapy water,then rinsed with clean water and dried.
Fig.7-10 shows the storage of safety belts on upper shelf.
Fig.7-10 Storage of Safety Belts on Upper Shelf
6.Preventive Test of Safety Belts
The preventive test of safety belt is mainly static load test,with a test cycle of 1 year(in which the test cycle of cowhide belt is half a year).