Measures for the safe construction of hazardous work laboratories
Safety is the first priority for work that comes into contact with dangerous goods. In the construction of such laboratories, people should estimate the possible dangers in advance, and then consider comprehensive construction measures, including the reasonable choice of materials and equipment, and the safety design of facilities.
Every work that comes into contact with dangerous goods faces the question: what protective measures must be taken under the existing space and technical conditions? The Laboratory Safety Operations Manual (BGI/GUV-I-850-0) answers these questions. This guide for laboratories provides detailed guidance on a variety of situations and is therefore widely circulated in other similar fields. Even for experienced laboratories or proven safety facilities, the book is instructive. It can be said that as long as the safety guidelines are strictly followed, preventive measures can be fully implemented in place.
Technical protection measures for hazardous work include both “hardware” and “software” levels. First of all, there must be the strictest requirements for “hardware” – materials and equipment, so that potential dangers can be put under control. In addition to protecting people and the environment from dangerous goods, these “hardware” also ensure the safety of auxiliary materials and equipment. In order to avoid the danger or control the danger within a short period of time and a low degree, it is necessary to implement various “hardware” measures. In addition, “software” – safety design – is also important because hazards exist in a variety of operating and working mediums. For example: high-temperature furnace work areas, dangerous goods operating stations and fume hoods, etc., their design must comply with high safety standards, in addition to the use of reasonable materials, but also have reliable protection and strict operation design. In short, safety design is present in every detail of the laboratory.
The following will mainly introduce the safety construction of hazardous work laboratories from the two levels of “material equipment” and “safety design”.
From a material and structural point of view, safety facilities and operating stations must withstand long-term chemical, mechanical and thermal stresses. Operator stations are often required to be smooth, non-porous, easy to clean and disinfect. The edge of the countertop should be slightly raised to prevent liquid from dripping. For two tables facing each other, a splashproof bezel should be set in the middle. Fume hoods with sinks or for other wet chemical operations can be equipped with large ceramic tables and sinks, which are not only non-porous on the surface, but also seamless at elevated edges, so that the operator station is resistant to chemical corrosion and high temperatures, while not afraid of scratches, easy to clean. Excellent materials allow the working environment to be maintained in a new state for a long time, and the safety standards stipulated are also strongly guaranteed.
In addition, using a patented process, a load-bearing test bench suitable for drying operations and ceramic sinks for wet chemical operations has been manufactured. The bench is made of cellulose fiber-reinforced phenolic resin with a fairly strong polyurethane acrylic surface. Thanks to the excellent antimicrobial properties of this surface, the application of the laboratory bench is not limited to physical and medical facilities, but also enters the field of pure studio. Antimicrobial properties stem from the density and cleanliness of the surface material. Polyurethane acrylic has a very high surface density, and bacteria, mold or other microorganisms are difficult to multiply on and cannot erode into the inside of the material. Therefore, the use of a test bench with such a surface does not require coating or other additional treatment. In addition, the surface is extremely corrosion-resistant, making it easy to clean it with corrosive media. At the same time, unlike traditional materials, polyurethane acrylic has a smooth and anti-pollution surface, which is impermeable to all clinical and biological experimental samples. This versatile material is also ideal for many indoor applications, which have been proven in painted walls and other areas that emphasize product life and ease of maintenance.
Laboratory dangerous goods must be reasonably stored and stored to ensure that they can withstand various stress stimuli and do not have dangerous reactions, while not endangering the safety of the environment and personnel. There are many ways to store dangerous goods: some can be stored externally, some should be stored in separate warehouses, and some can be stored directly in the safety cabinet at the operation site. Reasonable choices should be made according to the type of dangerous goods and the place of use. The storage of dangerous goods directly at the operation site should be certified by European standards, while avoiding excessive dangerous transportation, and some necessary media should also ensure that they are placed in place.
Safety cabinets are mainly divided into two types: one is used to store flammable liquids or high-pressure gas storage cylinders; The other is an acid- and alkali-resistant cabinet for storing corrosive substances. The current EU standard (EN 14470) specifies the structure and fire resistance of safety cabinets for the storage of combustibles and high-pressure gas storage cylinders. Fire resistance is the most important performance index of the safety cabinet, it must be guaranteed: once the fire, before the stored dangerous goods are ignited, people have sufficient time to take fire extinguishing and other first aid measures to ensure personal safety. The key to achieving this performance is the automatic closing technology of the cabinet door, which can also be used to integrate the alarm system with the ventilation device. The 90-minute fire cabinet is equipped with a foam seal and fire shield to isolate the internal and external high temperatures. If the door is opened beforehand, it will automatically close when the outside temperature is higher than 50°C. The performance requirements of the safety cabinet for storing acid and alkali are different, and this safety cabinet requires strong chemical resistance and high corrosion resistance of the internal board. They can even store acid, alkali and flammable liquids at the same time, but try to place the two types of dangerous goods separation layers and ventilate them separately.
In order to ensure the continuous supply of liquid and gas to the test bench and fume hood, it is stipulated that the pipeline must not only be fixed and installed, but also pass the sealing test, and must have a long-term and clear marking. There are one or more gas conduits that are disposed of side by side to have valves installed. At the same time, it is recommended to set up an easy-to-use main gate for all media supply in a safe place, and then install emergency valves with clear signs and easy to operate according to building conditions. If the line is longer, the emergency valve must be installed in more locations. In addition, to avoid confusion, the standard EN 13792 “Color Codes for Laboratory Instruments” also specifies the marking colors of the pipe outlet and valve devices.
Devices that come into contact with hazardous media must be constructed and materials to withstand intensive use. To this end, people use strong bolts, high-quality bonding technology and professional sealing rings to ensure the tightness of gases and other devices, the use of higher than the standard wall thickness to improve the stability of the device, while the use of electrostatic coating film process to create a highly resistant surface. In addition, the installation and layout of the device should be reasonable, even if the difficulty of installation is increased, it is necessary to ensure the simplicity and safe operation of the device. The outlet device of the gas pipeline should ensure that there is no risk even if it is opened carelessly. Fume hoods should be guaranteed to operate externally.
The laboratory must be equipped with enough ventilation units that are ready to operate. The ventilation rate of the ventilation equipment shall not be less than 25m3/h/m2. If necessary, the inlet air should be heated and the generation of piercing wind should be avoided. The requirements for the fume hood exhaust system are particularly stringent, and its structure and ventilation design must be carried out: to prevent dangerous concentrations or amounts of gas, vapor or dust from spreading into the laboratory space, and to prevent the production of explosive gas components in the fume hood, and the operator is also protected from splashing dangerous goods or glass fragments. As for the minimum standards to be observed in the construction of fume hoods, DIN EN 14175 has clearly stated it.
In addition, the exhaust gas washing equipment placed on the work site should also ensure maximum safety. They reduce the environmental pollution of exhaust gases while protecting exhaust systems and fans from corrosive gases. The rinsing equipment needs to use the efficient separation principle to maintain a low level of pressure loss, even when changing the eluent, to maintain a high degree of separation. The waste liquid generated by leaching, like the waste liquid of the laboratory, is required to be neutralized and treated according to the regulations before being discharged into the public sewer. The neutralization equipment can be placed directly in the waste liquid production site, such as the cabinet at the bottom of the fume hood.
Once the human body comes into contact with dangerous goods, it must be rinsed immediately, so emergency showers assume important first aid tasks. According to the regulations, the emergency shower of the laboratory must be effective within 5 s, in addition, every work point must be placed with an eyewash and ensure that sufficient water can be supplied immediately. It is particularly important to achieve fast and efficient first aid, emergency shower equipment should be configured as high as possible above the provisions of laws and standards. To this end, the shower head has been specially designed to optimize the intensity of the spray and the distribution of the water flow, so that in an emergency, people can easily remove damaged clothing and put the parts that come into contact with dangerous goods under the current. The nozzle of the eyewash is designed with an upward bevel, and the precise water flow will turn inward at 10 to 30 cm from the nozzle, so that the injured person can free his hands to the eye and assist in opening the eyes. This highly effective design can quickly reduce eye pain.