In chemical production, chemical installations have many potential safety hazards. Have you ever noticed them? This article has carried out a very comprehensive inventory of hidden dangers from the facilities and equipment to the production site. Let’s check it out together!

1. Equipment and facilities


1) The noise of the reducer is abnormal

2) There is a lot of oil on the reducer or frame

3) The plastic blades of the reducer are thermally melted and deformed

4) Machine seal and reducer are short of oil

5) Gasket leaks

6) The anti-static grounding wire is damaged or not installed

7) The safety valve has not been inspected annually, leaked, and the account has not been established

8) The thermometer has not been inspected annually and is damaged

9) The pressure gauge has not been inspected overdue, damaged or the material is blocked

10) The key reactors do not use double sets of temperature and pressure display, record alarm

11) The rupture disc has not been replaced, leaked, and no account has been established

12) The lower valve of the bursting disc is not opened

13) There is a risk of explosion and the reactor is not equipped with a bursting disc

14) There is abnormal pressure increase or material flushing due to high temperature, interruption of stirring, etc.

15) The bottom valve is easy to block when discharging

16) There is acid corrosion in stainless steel or carbon steel kettle

17) Overload operation such as the amount of material charged exceeds the specified limit

18) The damaged enamel in the enamel kettle is still used in corrosion, flammable and explosive places

19) The inner liner of the reactor is eroded and damaged at the steam inlet of the jacket

20) The pressure vessel has exceeded the service life, the manufacturing quality is poor, and it still leaks after repeated repairs

21) Pressure vessel without nameplate

22) Absence number identification or unclear

23) Failure to effectively isolate explosive-sensitive reactors

24) There is no safety checklist for important equipment

25) Lack of spare parts or spare machines for important equipment

Storage tanks, tank farms, tank cars

1) The liquid level gauge is blurred or damaged, blocked

2) The electrostatic ground wire is loose or not connected

3) Leakage at flange gasket

4) High storage tanks such as small platforms are not effectively fixed

5) The liquid level of the safety liquid seal does not meet the requirements

6) Atmospheric pressure storage tank for use under pressure

7) The charging amount exceeds the specified limit

8) There is no thermometer installed in the very temperature storage tank

9) The container is cracked and still in use

10) Frequent vacuum and nitrogen alternating loads cause damage to the storage tank

11) The low boiling point solvent or liquefied gas storage tank is exposed to direct sunlight

12) There is a risk of collision with transport vehicles in outdoor storage tanks, etc.

13) The holes in the cofferdam of the dangerous goods tank farm are not blocked

14) The protection embankment of the hazardous chemical tank area is not tightly sealed, and the rainwater drainage holes are opened arbitrarily

15) The shut-off valve leading to the drain pipe is in an unsafe state such as normally open

16) For the outlet pipelines of flammable or corrosive materials in the hazardous chemical tank area, the brackets are not equipped with suspension-type compression spring compensation measures or directly adopt flexible connection short pipes

17) There are no warning signs such as mobile phone ban, fire source ban, height limit and the speed limit in the hazardous chemical tank area

18) No leakage in the dangerous goods tank area, material feeding operation records and daily inspections

19) Tractors randomly enter the dangerous goods tank area

20) There are open flames or forest fires around the dangerous goods tank area

21) Illegal use of electricity such as electric stoves, electric teapots, and electric heating plates in the operation room of the dangerous goods tank farm

22) The tank truck has no grounding device at the loading and unloading site

23) No measures to prevent the operator from falling from the tanker

24) The tank truck enters the tank area without an effective flame arrester and unqualified vehicle condition (damaged lighting or brake failure)

25) The safety accessories (pressure gauges, thermometers, safety valves) of tanker storage tanks have no inspection date or are invalid

26) The tank body of the tanker does not indicate the next inspection date of the pressure vessel

27) No electrostatic drag chains, anti-virus equipment or valve leakage on the tank

28) The ground has not been left to stand for more than 10 minutes before and after unloading

29) When the tanker is unloading, the driver and escort leave the unloading site without on-site guardians

30) Adopt open and splash discharge

31) Make the storage tank exceed the standard liquid level or overflow when the material is unloaded

32) When the vinyl chloride tanker is unloading, the hose or flange leaks

33) When vinyl chloride is transported and fed, the tank is full

34) The tanker was transported and unloaded in the factory many times when the loading capacity was not enough

35) The unloading vehicle is turned off and the hand brake is applied, or the vehicle is started during unloading

36) When high-strength lightning and lightning strikes are frequent, engage in unloading operations

37) There are no two grounding points of the oil tank

38) When loading and unloading gasoline and toluene, the operator did not wear anti-static overalls and anti-static shoes

39) There are no accident cofferdams and emergency spray dilution facilities in the storage area of ​​liquid ammonia and other storage tanks

40) Emergency shower and eyewash facilities are not set up on site

41) There are no measures to prevent misloading of materials such as ethyl acetate into gasoline tanks

42) Electric welding while standing on a petrol can

43) Unwashed, cut gasoline drums or welded sumps

44) Liquid ammonia and vinyl chloride storage tanks are overfilled

45) When the tank truck is unloading, it blocks the fire exit and encroaches on the road

46) The receiver leaves the unloading site

47) Use iron, plastic and other tools that are prone to sparks at the loading and unloading site

48) There is no operation record for the material storage tank sent from the tank farm to the workshop

Condenser, reboiler

1) Corrosion, gasket aging, etc. cause leakage

2) The material temperature is too high after condensation

3) The heat exchange medium layer is blocked by sludge and microorganisms

4) No protection for hot surfaces

5) When cooling high-temperature liquid (such as 150°C), the cooling water inlet and outlet valves are not opened, or the amount of cooling water is not enough

6) When the evaporator is used for the first time, the temperature rises rapidly

7) The heat exchanger does not take anti-vibration measures into consideration so that the pipes connected to it are loosened and leaked due to vibration

Pipes and Fittings

1) After the pipeline is installed, the internal welding slag and other foreign matter have not been cleaned

2) Sight mirror glass is not clean or damaged

3) The material of the sight tube is not suitable for pressure resistance and temperature resistance, and the sight tube is not installed properly

4) The optic tube is broken or used under pressure for a long time

5) The anti-static ground wire is damaged

6) Pipes, flanges or bolts are severely corroded and cracked

7) High-temperature pipes are not insulated

8) The explosion vent pipe is made into a bent pipe

9) Pipeline material and flow direction are unclear

10) The color code of the pipeline is unclear

11) Valves connected in series with different materials are not blinded during commissioning

12) Abandoned pipelines are not cleaned up in time

13) The installation position of the pipe valve is low, easy to hit the head or difficult to operate

14) No protective measures are taken for corrosive material pipelines, flanges and other places prone to leakage

15) There is the possibility of water, nitrogen, air, steam, etc. entering the material pipeline

16) Iron drums or plastic drums with flammable and explosive materials placed beside high-temperature pipelines

17) Unreasonable material selection for pipes or pipe fittings, easy to corrode

18) The glass tube liquid level gauge has no protective measures

19) No protective metal mesh is installed at the sight glass that may explode

20) The check valve cannot act flexibly or fails

21) Electric valve power failure, pneumatic valve power failure

22) The use of pressure pipelines such as hydrogen without regular maintenance or operation with disease

23) When using pressure pipes, the operators are not trained or certified

24) Maintenance personnel have no qualifications to repair and transform pressure pipelines

25) The welding quality of the pressure pipe is poor, and there are welding defects such as undercut, air hole, slag inclusion, and incomplete penetration

26) The pressure pipeline is not equipped with safety accessories in accordance with the regulations or the safety accessories have not been calibrated within the time limit

27) The pressure pipeline has not established files and operating procedures

28) Glass-lined pipes are impacted by steel pipes, etc.

29) After the production process medium is changed, the existing pipeline valves are still used without considering the material adaptability

30) The nitrogen pipe is connected in series with the air pipe

31) The brine pipe is connected in series with the cooling water pipe

Transfer pumps, vacuum pumps

1) Pump leaks

2) Abnormal noise

3) Coupling without protective cover

4) No pressure gauge or check valve installed at the pump outlet

5) When the pump is not used for a long time, the liquid in the pump and pipeline is not drained, causing corrosion or freezing

6) When the displacement pump is running, the outlet valve is closed or the safety return valve is not installed

7) The diameter of the pump inlet pipe is small or the pipe is long or has many turns

8) The installation height of the centrifugal pump is higher than the suction height

9) Anti-static belt not used


1) The filter solvent is not filled with nitrogen or the nitrogen pipeline is blocked or there is no flow meter on site to display

2) When the centrifuge is used to filter the solvent in the fine drying bag, the oxygen meter and alarm device are not installed

3) Quickly brake or brake with auxiliary tools (such as iron rods, etc.)

4) The centrifuge is not effectively grounded

5) Anti-static belts are not used in the explosion-proof area

6) When the centrifuge is running, the vibration is abnormal

Double Cone (Double Cone Rotary Vacuum Dryer)

1) No guardrail and safety interlock device

2) Personnel climb into the double cone to replace the vacuum bag

3) Drive belt without protection

4) Shaft seal leakage

5) The vacuum line is blocked or the vacuum valve is not opened during use


1) Gas cylinders are not equipped with bottle caps and shockproof rings

2) When hydrogen cylinders are transported and stored in summer, there are no sunshade measures, resulting in exposure to the sun

3) Some gas cylinders have exceeded the annual inspection period

4) When acetylene cylinders and oxygen cylinders are used at the same time, the safety distance shall not exceed five meters

5) Close the hydrogen cylinder valve with catalyst gloves

6) Hitting the cylinder

7) After the gas cylinder is used, the air pressure is less than 0.05Mpa

8) Gas cylinder group and pipeline connection, valve damage

9) When the hydrogen cylinder is used, no anti-static device is used or it is damaged

10) There is no anti-falling measure for gas cylinders

11) There are trenches and secret passages in the storage place

12) The storage place is not ventilated or not well ventilated or corrosive gas enters

13) Lack of fire extinguishing equipment

14) Use the acetylene cylinder upside down

15) The color of the cylinder is blurred


2. Electrical instruments

1. Non-explosion-proof electrical appliances or non-explosion-proof control cabinets are installed in the explosion-proof area

2. The window glass of the power distribution room is broken

3. There are many sundries in the power distribution room

4. There are steam water, material pipes, dust and corrosive substances in the power distribution room, which will cause the electrical equipment in the power cabinet to age and cause short-circuit accidents

5. There is acid mist corrosion or solvent infiltration or a lot of dust outside the transformer

6. There are clothes and other sundries behind the control cabinet or transformer cabinet

7. The power distribution cabinet is too old and prone to short circuit

8. The cable is close to the high temperature pipeline

9. Leakage of material pipelines and sewage pipelines around overhead cables, causing corrosive materials to flow into the cable tray

10. Buried cables are corroded by groundwater

11. Serious infiltration of sewage in cable wells and ditches

12. The cable tray is severely corroded

13. The cable protection sleeve is aging and broken

14. When the cables or steel pipes for laying electrical lines pass through the holes in the walls or floors between different places, they are not strictly blocked by non-combustible materials

15. Randomly pulling the movable exhaust air, causing the cable connector to fall off and leakage of electricity

16. The switch button corresponding to the device tag is unclear

17. There are messy and unknown cables in the workshop

18. Emergency lights are not installed or broken

19. Outdoor motor without protective cover

20. The illumination of the operation site is not enough

21. The equipment and the electrical equipment are not matched (small cow tow cart, old cow tow cart), resulting in heat damage and fire of electrical equipment

22. Flushing water on electrical equipment and cable trays

23. The screw of the explosion-proof mirror lamp and lighting lamp is loose, and the light leaks

3. Static electricity

24. In flammable and explosive places, the reactor, pipeline, storage tank, condenser, delivery pump, flange, and valve are not grounded or not well grounded

25. In flammable and explosive places, the powder feeding hopper is not grounded and filled with nitrogen

26. Transporting gasoline, toluene, cyclohexane and other liquids exceeding the safe flow rate (v2<0.64/d)

27. The hydrogen flow rate in the main pipe exceeds 12m/s, and the branch pipe exceeds 8m/s

28. Spray gasoline, etc. from a high level into the bottom of the storage tank or the ground

29. When nitrogen is not filled, aluminum isopropoxide, magnesium powder, etc. are put into the reaction kettle containing gasoline, toluene, etc. from the open funnel

30. In flammable and explosive places, put on and take off clothes, shoes and hats and perform strenuous activities

31. In flammable and explosive places, use chemical fiber material mop or rag to wipe equipment or ground

32. Filling gasoline into plastic barrels

33. Use solvents such as gasoline to wash work clothes or mop the floor or steel platforms and floors

34. The walls of stainless steel and carbon steel storage tanks are not grounded with welded steel bars or flat steel, and there are no two grounded places exceeding 50m2

35. There are places where flammable and explosive gases are emitted, and measures to eliminate static electricity hazards such as humidification are not adopted

36. Use plastic pipes to suck or fill toluene or recycle toluene

37. Conveying or stirring petrol with compressed air

38. Anti-static slippers are not used in the explosion-proof clean area

39. The grounding flat steel and the lightning protection belt on the roof are rusted and severely corroded

40. The unwelded reinforcement of the metal equipment above the roof is incorporated into the lightning protection belt

4. Production site

41. Storage of more raw materials or waste

42. There are many “running, leaking, dripping and leaking” on site

43. Damaged insulation

44. Lack of effective guardrails

45. Normally closed fire door normally open

46. ​​Operation posts with dust (magnesium powder, zinc powder, etc.) are not cleaned up in time

47. Metal sodium and sodium hydrogen are stored without rainproof measures or waste barrels and waste bags are stored randomly

48. Fire exits are blocked or various pipelines and their supports obstruct passage

49. The fire extinguisher is missing or expired, or the fire belt and fire hydrant do not meet the fire protection requirements

50. Waste bins have multiple labels

51. Strong oxidants (hydrogen peroxide, potassium permanganate, etc.) are stacked on wooden shelves

52. The steel platform shakes too much

53. Severe corrosion of steel platforms or columns

54. The concentration of solvents in local areas exceeds the standard

55. High valve handles, iron rods, etc. are easy to fall

56. The concrete floor vibrates greatly

57. There are many sundries on the outdoor steel shed or roof

58. Expiration or failure of anti-virus equipment

59. Non-production utensils (food, newspapers, novels) are stored at the production site

60. Lack of heatstroke prevention and cooling facilities in summer

61. Outdoor small-diameter water pipes are not insulated in winter

62. Sanitation facilities such as emergency showers and eye washes are not available or damaged in the workshop

63. Vehicles entering the production site without flame arresters

64. The combustible gas alarm device is not installed or fails in the flammable and explosive places

65. Reactors, storage tanks, pumps, etc. are not labeled with equipment tag numbers and names

66. There is no fixed bolt on the big iron gate, once the wind is strong, the iron gate may spark and cause danger

67. The threshold of the warehouse is low, once an accident occurs, dangerous goods will overflow

68. Storage of iron plates and steel pipes on the ground at the production site

Five, personnel, on-site operation

69. No job operation records or incomplete operation records

70. Suction, filling, and handling of corrosive materials without wearing protective equipment

71. There are phenomena such as operators leaving their posts, leaving their posts, and sleeping on their posts

72. Dust masks are not worn at powder and other feeding posts

73. Quick switch valve

74. The stratified kettle and tank bottom valve are not closed after stratified

75. The water diversion valve of the layered kettle and the tank is too large, causing the oil in the water to be discharged into the sewage pool or the drainage time is too long and the valve is forgotten to run out of material

76. Put air into the high temperature kettle and tower

77. Extraction catalysts (such as palladium carbon, active nickel, etc.) are scattered on site

78. Using iron rods to poke pipes, clogged materials in kettles or use non-explosion-proof equipment to generate sparks

79. Noisy Environment without wearing ear protection or earplugs

80. Overpressure use of storage tanks

81. Where flammable and explosive solvents such as gasoline and toluene are used, the kettles and tanks are not replaced with nitrogen

82. Smoke, poor ventilation or lack of oxygen

83. Open the lid of the reactor under pressure

84. Employees have occupational contraindications or allergies or have been in contact with poisons for too long

85. Emergency valve or emergency switch is not easy to operate

86. In flammable and explosive places, wear shoes with spikes or high heels, sandals

Six, Civil engineering

87. There are no preventive measures for the pipeline wells on the upper and lower floors where the fire may spread (such as blocking with flame-retardant materials)

88. Explosion-proof walls and light-weight roofs are not used in processes with explosion hazards, or adequate explosion-venting surfaces are not considered

89. The number of entrances and exits and emergency passages is not enough or blocked or there is no obvious sign

90. The foundation of the factory building has been corroded by acid and alkali substances, and the columns and beams have been seriously damaged

91. When there is a strong wind, the glass of the steel window is easy to fall off

92. Stairs that are too narrow or steep

93. Poor indoor drainage or long-term water and oil accumulation in low-lying places

94. There is not enough space above the head and ceiling in the passage or working place

95. In the case of unknown underground pipelines (water pipes, cables, etc.), excavate the road at will

96. Use of large machinery to excavate near underground cables, pipes, etc.

97. When a fire broke out in the fire-prohibited area, the production workshop did not send people to monitor it

98. Abnormal situations (pipeline breakage, leakage, etc.) occurred during construction, and the construction was not stopped immediately for emergency treatment

99. Digs, pits, ponds, etc. and damaged pipelines, without fences and signs, and without lighting at night

100. When the soil is found to be likely to collapse or slide, the operation is not stopped

101. There are no measures to prevent underground empty tanks and pools from floating

102. Failure to go through the corresponding approval procedures or follow the approval requirements (such as labor protection supplies, guardian implementation, etc.) when carrying out the tank and pool operations, and operating without the precautionary measures in place

103. During non-civil construction operations, failure to go through the “non-infrastructure employment procedures” or not understanding the corresponding possible risks before operation, and starting work without safety measures in place

Seven, production maintenance

104. When cleaning and overhauling in the container, there is no emergency escape facility or measure in case of dangerous situation

105. There is no guardian for hot work or the guardian is a new employee or the fire is violated

106. Overload lifting

107. Tools or loads not properly secured

108. Not equipped or not wearing protective equipment (hard hat, safety belt, etc.)

109. There is no warning sign or the sign is blurred (such as preventing electric shock, preventing falling objects, etc.)

110. Stepping on suspended pipelines or small-diameter plastic pipelines and glass-lined pipelines or using unsafe climbing facilities during maintenance

111. Leakage caused by damage to cables such as electric welding machines and manual electric tools, and zero wire damage or jumping

112. Blindly entering sewage ponds, deep ditches, and deep pools for operation

113. The pipe frame is icy and slippery in winter, without anti-skid measures

114. The welders of the installation company have no welding certificate or the maintenance workers have not received relevant training

115. Working directly on the roof of fragile materials such as asbestos tiles and linoleum

116. When working at high places, cross-operation without taking precautions

117. When working at high places, the zero line of the electric welding machine is not connected to the welding position

118. Failure to wear a gas mask when working in areas with peculiar smell or the possibility of producing toxic gases

119. No safety fences or safety nets are installed when repairing or digging holes at high places

120. The cleared hazardous materials are scattered from the upper floors to the lower floors

121. Carrying people by hoisting machinery

122. Insufficient lighting for night work

123. In the event of strong winds above grade 6 or other severe weather, still working at heights in the open

124. When working in the kettle, there are no more than two people outside the kettle to supervise

125. During the maintenance in the kettle, the power supply was not cut off and a sign saying “Manned maintenance, no closing” was hung

126. Before entering the tank, the tank was not cleaned effectively

127. Before entering the tank, the concentration of combustible gas, oxygen content and toxic gas (CO, H2S) concentration were not analyzed

128. Before entering the tank, the material pipelines such as raw material, solvent, steam, water, nitrogen and other pipelines are not reliably isolated

129. During the maintenance process, regular sampling and analysis of the kettle was not carried out

130. There is no sign “There are people in the tank” on the obvious place outside the kettle

131. When entering the tank, the “double inspection system” was not implemented

132. The lighting in the kettle does not meet the safety voltage standard, the voltage is greater than 24V in dry conditions, and greater than 12V in wet conditions

133. After the inspection and maintenance are completed, the machine is turned on without checking and cleaning up the sundries

134. Working in the kettle for a long time without rotation

135. During maintenance, there is a lack of necessary ventilation facilities in the kettle

136. Welding on the outer surface or inner wall of glass-lined tanks

137. Entering the glass-lined kettle, no soft cushion is laid in the tank

138. Rapid heating or rapid cooling of glass-lined kettles

139. When using glass-lined tanks, the tank mouth or manhole bolts and clips fall into the tank

140. When using a glass-lined kettle, stainless steel kettle, or carbon steel kettle, the acid liquid enters the jacket of the kettle

141. The selected materials have not been reviewed for temperature, PH, corrosion solubility, and the places where there may be pressure have not been reviewed for special pressure

142. After the overhaul is completed, all spaces such as the inside of the kettle and the high and low positions of the overhaul site have not been fully cleared and reviewed, and the trial operation has started

143. After the overhaul is completed, the relevant matters have not been fully communicated, the changes have not been confirmed and approved, and the relevant personnel have not been fully trained and understood before taking over

144. Feed production without operation confirmation for inspection and maintenance

8. Production process

145. There is an emergency response, and there is a lack of response measures and training

146. Changing the feeding amount or feeding ratio at will

147. Improved process or new process without a safety assessment

148. Process changes have not been strictly reviewed and approved

149. Process operation within the explosion limits of combustible gases

150. When using highly toxic materials, use open operations

151. Trial production without preparation of process operation procedures

152. The physical properties of the materials used and precautions for safe use have not been prepared

153. When the materials used to decompose, the heat generated has not been accounted for in detail

154. Dust explosion potential present

155. When a certain raw and auxiliary material cannot be put in in time, there is a danger in the temporary storage of the material in the kettle

156. Hazard of spontaneous combustion or polymerization or decomposition of raw materials or intermediates in storage

157. Various parameters (temperature, pressure, etc.) in the process are close to the dangerous limit

158. In the event of an abnormal situation, there is no measure to quickly discharge the reactant

159. Absence of measures to prevent and suppress violent reactions

Pressure Vessel
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