Abstract: In recent years, the scale of pharmaceutical and chemical companies in our country has been continuously expanding. The situation in pharmaceutical and chemical companies is complex, and accidents such as fires or explosions can occur with a slight oversight, causing immense damage to human life and property, leading to tragedies. Therefore, it is particularly urgent to implement the "Three Simultaneous" principle, timely propose countermeasures for issues that arise, eliminate inherent hazards, and avoid affecting the company due to fire safety issues, thereby enhancing the company's safety level. Based on national regulations, documents, and the author's years of practical experience, this article provides a brief discussion and analysis of explosion-proof fire safety design in the renovation of pharmaceutical and chemical factory buildings.
[Keywords]:Pharmaceutical & Chemical Industry; Cleanroom Explosion-Proof Design; Renovation; Fire Protection Modification
0 Preface
In recent years, due to the short product lifecycle in the pharmaceutical market, companies have had to construct new factories or renovate existing ones to meet the hardware and software requirements of new processes and equipment. For instance, the emergence of the COVID-19 pandemic has led companies to typically upgrade and renovate existing facilities to produce new drugs or vaccines at an accelerated pace. However, the pharmaceutical and chemical industry is complex, especially for cleanroom production facilities, which, due to their unique architectural design, layout, construction, and production equipment, greatly increase the fire risk. The variety of production processes involved, along with the highly flammable, explosive, and toxic nature of pharmaceutical raw materials, pose significant risks in the event of a fire, potentially causing immense harm to human life and property. Renovating old factories is particularly challenging due to the inability to alter the original structural attributes, leading to more complex fire safety design modifications and a higher number of issues. Therefore, renovations in this area must adhere to the "three simultaneous" principle, promptly address emerging issues, eliminate inherent fire hazards, ensure the effective operation of fire safety facilities, enhance the safety of chemical enterprises, and ultimately guarantee fire safety to prevent any impact on chemical businesses.
Basic Characteristics of Fire Safety in Pharmaceutical and Chemical Enterprises
Due to the industry characteristics of pharmaceutical and chemical enterprises, they are prone to explosions and fires, making them key units for fire safety. Specific attention should be paid to fire hazards in the following aspects:
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- Raw materials are mostly hazardous chemicals, with high explosive and toxic hazards.
In the production process of pharmaceutical and chemical enterprises, the raw materials and auxiliary materials often involve hazardous chemicals, which are typically sensitive and explosive. They are prone to ignition from external factors such as heat, mechanical impact, friction, shock waves, detonation waves, light, and electricity, posing significant dangers. Moreover, many of these substances are toxic, and their explosion can release toxic or asphyxiating gases, leading to poisoning and asphyxiation.
1.2 Highly flammable, prone to spreading fires and forming flowing flames.
In the event of fires or explosions at pharmaceutical and chemical companies, a large-scale spreading fire can be triggered instantly, resulting in severe consequences.
Firefighting efforts faced significant challenges and high risks.
Pharmaceutical and chemical companies have complex processes with high levels of automation, numerous floor openings in their buildings, and dense arrays of tall equipment. In the event of a fire, this can lead to rapid spread of the flames, greatly increasing the difficulty of extinguishing the fire. Due to GMP requirements, cleanrooms are well-sealed and airtight, with no windows in the production area. Additionally, with a high presence of toxic and harmful substances, contact reactions and the release of toxic gases are likely during combustion and firefighting. This, coupled with the extreme difficulty in selecting appropriate firefighting agents and protective measures, makes the rescue operation even more perilous.
Current fire safety issues in pharmaceutical and chemical companies
With the adjustment of national standards in recent years and the emergence of new regulations, many pharmaceutical and chemical companies' factories, which were constructed early on, are now struggling to meet the requirements of the new standards.
It is necessary to analyze the current fire safety issues in pharmaceutical and chemical enterprises, make improvements, and meet the new regulations' requirements for fire and explosion prevention safety.
2.1 Conflict between the original factory structure, fire resistance grade, and current regulations
The factory's fire resistance rating may be Class D, the factory structure is steel-framed, and even the building's use is for residential purposes.
2.2 Fire protection distances in buildings do not meet requirements
Many pharmaceutical and chemical companies, after multiple upgrades and technical transformations, have expanded their existing facilities or temporarily constructed new ones, occupying fire lanes and failing to meet safety requirements for fire separation distances from surrounding buildings. The newly added Class A explosion-proof areas within the factory do not meet the required safety distances for explosion venting.
2.3 Fire Protection Zone Adjustment
Increasing large openings in the existing structural floor and re-zoning the existing production areas will affect the current fire compartmentation divisions.
Optimized Explosion-Proof Fire Protection Design for Pharmaceutical and Chemical Industry Factory Renovation
3.1 Ensure the "Three Simultaneity" is genuinely achieved
Safety facilities for new, reconstructed, and expanded engineering projects must be designed, constructed, and put into production and use simultaneously with the main project [1].
3.2 Strict fire separation control
According to the Code for Fire Resistance Design of Buildings, GB50016-2014 (2018 Edition)[2], the fire resistance grade of buildings is generally divided into four levels based on the combustion performance and fire resistance limit of building components (beams, columns, floor slabs, walls, etc.). In general, pharmaceutical and chemical factory facilities and warehouses primarily consist of Class A, B, and C.
Therefore, it is necessary to accurately determine whether the original fire resistance level of the existing factory design meets the requirements. In principle, the fire resistance level design and usage nature of the existing buildings should not be altered. When dealing with buildings that do not meet the fire resistance level requirements, a new location for renovation must be selected. Therefore, attention should also be given to the following points during the renovation: first, whether the protective layer has peeled off or deteriorated; if so, it should be reinforced. Second, for areas that have already been reinforced, a concrete mortar layer should be used for fire protection before renovation. Third, components that were originally treated with fire-resistant steel structural coatings must pass a quality inspection and be deemed合格 before they can be used again.
March 3rd - Strictly Control Fire Protection Distances
Fire separation distances are the safe spacing requirements that prevent adjacent buildings from being ignited by a fire within a certain time frame. In the design of renovations, it is crucial to strictly adhere to the regulatory specifications for controlling the fire separation distances between buildings.
During the redesign, the fire separation distances for existing附属物 outside the building must also be recalculated. A new local Class A explosion-proof area has been added, necessitating a re-evaluation of its fire separation from surrounding areas. The distance to significant public buildings must be greater than 50m, and for areas with open flames or sparks, the distance should be over 30m.
In case of difficulties during actual design, the following measures can be adopted: 1. Convert the higher exterior wall into a solid fire-resistant wall, or change the exterior wall below 15 meters of the roof of a building taller than the adjacent one into a fire-resistant wall; no doors, windows, or openings are allowed on the fire-resistant wall. 2. Add fire separation water curtains or fire curtains, which must comply with the requirements of GB50084-2017 "Code for Design of Automatic Sprinkler Fire Extinguishing Systems." 3. Adjust the process, relocate hazardous process steps, modify the layout to reduce the risk to the existing building's operational functions, and adjust the layout accordingly.
3.4 Reasonably set fire separation partitions
For new openings in floor slabs and fire-resistant walls, fire-resistant partitioning must be used, or the openings must be sealed with fire-resistant materials. However, for openings like those in reaction vessels that cannot be sealed, the fire compartment area must be recalculated based on the requirement that the areas above and below are considered the same fire compartment. Ensure that the new fire compartment area does not exceed the specified requirements. If the fire compartment area exceeds the regulations and the original design did not include a fire-suppression automatic灭火 system, according to the "Building Design Fire Code" GB50016-2014 (2018 Edition) regulation "3.3.3", the fire area can be doubled by adding an automatic fire-suppression system.
The new fire separation zones require a re-evaluation of the fire safety evacuation distances within the areas. If necessary, a shared antechamber should be added at the evacuation staircases to utilize the疏散staircases of adjacent fire separation zones. The new fire-rated partitions must be built up to the bottom of the structural beams, and the gaps between the steel roof and fire-rated partitions must be sealed with fire-resistant boards. To minimize the impact of the new fire-rated partitions on the existing structure, lightweight pre-fabricated fire-rated partitions can be used. Along with adjusting the fire separation zones, the entire fire protection design, including HVAC smoke extraction design, fire hydrant design, and fire sprinkler design, must also be modified.
3.5 Class A explosion-proof design
For Class B factory buildings with newly added Class A explosion-proof areas, if the total area of the floor or fire compartment does not exceed 5% of the floor or fire compartment's total building area, the floor or fire compartment may still be designed as a Class B fire hazard factory. The Class A area requires corresponding explosion-proof design for all specialties: such as reducing the fire compartment area, shortening the evacuation distance, using non-sparking floors, explosion-proof walls, explosion relief measures, explosion-proof electrical requirements for the electrical specialty, wiring and control methods, lightning protection design, static grounding of pipes and equipment, flammable gas detection, explosion-proof ventilation and emergency exhaust design for the HVAC specialty, new fresh air air conditioning system design, explosion-proof for supply and exhaust fans, etc. In the design, the Class A area must be separated by solid explosion-proof partitions, and the windows on both sides of the explosion-proof walls within 2.0 meters of the ends (close to the edge) must be sealed. Due to the high floor load requirements of solid explosion-proof partitions on existing buildings, lightweight prefabricated explosion-proof partitions will be used in actual renovations, with necessary buffer explosion-proof door bays. When using external wall explosion relief, the external walls of the explosion-proof area must be changed to explosion relief walls, with explosion relief walls attached with tension lines to prevent the walls from being propelled out and causing secondary injuries during an explosion. For factory buildings with existing steel structures, after the explosion-proof areas are set, the existing steel structure system must be assessed and reinforced to ensure that the structural stability is not compromised in the event of an explosion.
Emergency Evacuation System Selection
In summary, during the pharmaceutical production process, the production environment often involves corrosive substances, explosive gases, dust, and other factors that may lead to explosions during fires, resulting in significant economic losses and casualties. Therefore, in the construction, renovation, or expansion of pharmaceutical chemical plant workshops, it is necessary to re-plan evacuation routes, install emergency evacuation guidance systems, and also meet the explosion-proof requirements for electrical equipment installed in explosion-proof environments.
In industrial pharmaceutical factory buildings, the selection of emergency evacuation systems is generally "centralized power supply with centralized control." The corresponding product selection is as shown in the following table and chart.
Controller Main Unit and Central Power Supply Selection
Conclusion
The original intention of the fire protection design and renovation is to safeguard the lives and property of the nation and its people, be responsible to the construction entity, and create safe production conditions for them. Only through further exploration and implementation of effective measures for the fire safety of pharmaceutical and chemical enterprises, adhering to the "three simultaneous" principle, can we maximize the safety of production, reduce hidden fire risks, and avoid blindly pursuing an absolute sense of security.
Reference
- The "Production Safety Law of the People's Republic of China" (Passed by the Standing Committee of the 12th National People's Congress on August 31, 2014, and effective as of December 1, 2014)
[2] "Code for Fire Prevention in Building Design (GB50016-2014 2018 Edition)" [S]
[3] Zhuang Yijun, Shen Bei. Analysis of Major Issues in Fire Design of Existing Building Renovation [J]. Fire Science and Technology, 2010, 29(11): 972-974+983.
Huang Chengjie, Liu Xiaojuan. Discussion on Fire Prevention and Explosion Protection Safety Design in the Reconstruction of Pharmaceutical Chemical Industrial Plants [J]. Chemical Industry Management, 2020, No. 557(14): 74-75.
[5] Ankorri Enterprise Microgrid Design and Application Manual, 2022.05 Edition
