Fire sprinkler systems are one of the most effective ways to protect life and property in case of a fire. However, ensuring their reliability starts with high-quality sprinkler head frames. Producing these components requires a detailed, multi-step process to ensure their functionality, durability, and compliance with safety standards. In this article, we’ll walk you through the critical steps involved in producing fire sprinkler head frames, from design to quality control.

Now that we’ve covered the basics, let’s dive deeper into each step of the production process.

Step 1: Design the Drawing

The first step in producing fire sprinkler head frames is creating detailed design drawings. Before starting the design, it’s essential to define the type and specifications of the sprinkler head. This includes selecting the right material, determining the dimensions, and specifying critical features such as orifice size and thread type.

Confirm Key Parameters
The orifice size directly influences the sprinkler head’s K-factor, a critical parameter that determines the flow rate of water through the sprinkler. Accurate calculations must be made to ensure the orifice size is optimal for fire suppression in the specific environment. Additionally, the thread type must comply with local standards, such as the GB/T 7306.2 thread standard in China. Ensuring compatibility with local building codes and installation practices is vital.

Material Selection

Currently, most fire sprinkler head frames are made from brass, with only a small percentage using stainless steel. The reasons for choosing brass are:

Corrosion Resistance: Brass maintains stability in various environments, resisting corrosion and ensuring a long lifespan, even in high-moisture conditions.

Durability: Brass is highly durable and can withstand high water pressures and temperature fluctuations, making it ideal for fire protection systems.

Excellent Machinability: Brass has excellent processing properties, making it suitable for various manufacturing techniques, including casting, forging, and stamping.

After selecting the material, it’s easier to choose the appropriate mold material and machining tools, ensuring compatibility and efficient production.

Branding and Identification
On the frame design, there should be space allocated for the manufacturer’s brand or manufacturer code. This is usually indicated in the blank areas on either side of the frame, ensuring that the product can be traced back to the producer for quality control, warranty, and regulatory purposes. This aspect should be carefully planned during the design phase to ensure proper placement and visibility.

Compliance with Fire Safety Regulations
The design must comply with the relevant fire safety regulations of the local jurisdiction. These regulations may vary by region, but they generally cover aspects such as material composition, operational temperature ranges, and other safety factors. Ensuring compliance with these standards during the design phase helps prevent costly revisions during later stages of production and guarantees that the final product will meet safety requirements.

Step 2: Make Molds

Once the design is finalized, the next crucial step is making the molds for the fire sprinkler head frame. Molds are essential for shaping the frame accurately, and the precision of this step directly impacts the quality and functionality of the final product.

Mold Materials
To increase the durability and lifespan of the molds, it’s essential to use high-quality mold materials. These materials must be resistant to wear and tear, as they are subjected to repeated use during production. Premium-grade metals and alloys should be selected to enhance the mold’s resilience, ensuring that it can withstand high pressures and temperatures during the casting or forging process without losing shape or accuracy over time.

Mold Precision
The precision of the mold is critical in ensuring that the sprinkler head frame is accurately shaped to the specifications in the design. Even the smallest deviations in the mold can result in defective frames that may not meet the required performance standards. A high degree of accuracy is necessary, particularly in the orifice and thread areas, which must align perfectly for the frame to function correctly within the sprinkler system.

Step 3: Hot Forging or Die Casting 

Once the mold is completed, the next step is to shape the sprinkler head frames. There are two common methods for shaping these frames: Hot Forging and Die Casting.

What is hot forging to shape sprinkler frames?
Hot forging is a manufacturing process where the metal is heated to a very high temperature but remains in a solid state. It is then forced into an open die until it takes the desired shape. This process results in metallurgical recrystallization and grain refinement, which enhances the material’s density and mechanical strength. Forged parts are generally stronger and more durable.

What is die casting to shape sprinkler frames?
Die casting, on the other hand, involves heating the metal until it becomes molten and then forcing it into a closed die, where it cools and solidifies into the desired shape. This method is often described as the shortest path from raw material to finished product. Die casting produces parts with excellent surface finish and consistent dimensions.

Hot Forging vs. Die Casting: How to Choose?

When deciding between hot forging and die casting for producing fire sprinkler head frames, several factors come into play. Below is a comparison of both processes:

Factors	Hot Forging	Die Casting
Durability and ductility	★
No porosity, shrinkage, cavities	★
Surface finish and dimensional precision		★
Process Stability and Production Efficiency		★
Material Scrap		★

 

From the above table, it’s clear that each process has its strengths. Hot forging excels in durability and material utilization, while die casting is better for achieving precise surface finishes and production efficiency.

In China, hot forging remains the most commonly used method for producing sprinkler head frames. This is mainly due to its lower equipment and mold costs compared to die casting, making it a more cost-effective option. However, depending on local fire sprinkler certification requirements, the choice between the two processes may vary.

Step 4: Machining

After the parts are formed, they undergo precision machining to refine the forming parts. This step involves several key processes, including drilling holes for the water inlet and deflector rivet, turning threads for system connections, and surface polishing to improve both functionality and appearance.

The threads are carefully machined according to international standards, such as NPT (National Pipe Thread) or BSPT (British Standard Pipe Thread), depending on the target market and regional requirements. This ensures compatibility with other system components and prevents leaks or malfunctions. Accurate alignment of the holes and threads is crucial to guarantee that the frame fits properly within the sprinkler system and performs reliably under pressure.

Once machining is completed, the sprinkler head frame is ready for the next stages of assembly and surface treatment.

Step 5: Surface Treatment

Surface treatment is crucial for enhancing the durability, corrosion resistance, and appearance of sprinkler heads. The most commonly used surface treatments include chrome plating, white coating, and neutral brass finishes.

Chrome Plating: This process involves an electrochemical reaction that deposits a layer of chrome on the surface of the sprinkler frame. Chrome plating significantly improves corrosion resistance and adds a glossy finish, helping the sprinkler head withstand harsh environments.

Powder Coating: Plastic powder is electrostatically applied to the frame, then baked at high temperatures to form a smooth, durable coating. This provides excellent adhesion, mechanical strength, and superior corrosion and abrasion resistance. The white color is often chosen to match ceiling aesthetics in both residential and commercial settings.

Neutral Brass: In this process, copper is treated with a passivating solution, forming a protective film that prevents oxidation and discoloration. This finish preserves the brass’s shine and offers long-lasting oxidation resistance without affecting the material’s conductivity or weldability.

Each of these treatments not only protects the metal but also ensures the sprinkler heads remain functional and visually appealing for many years.

Step 6: Quality Control

The final step in the production process is rigorous quality control. The inspection process includes several critical checks:

Dimensional Accuracy: The frame’s dimensions, particularly the water outlet hole size, must be within strict tolerances. Any deviation can impact the sprinkler’s performance and water distribution.

Weight Check: Each sprinkler head must meet its designed weight specification, with a permissible deviation of no more than 5%. This ensures consistency in manufacturing and functionality.

Thread Inspection: The interface threads must conform to international standards (such as NPT or BSPT). Thread gauges are used to verify the accuracy and compatibility of the threads, ensuring proper connections to other system components.

Surface Finish: The external surface of the frame should be smooth, uniform, and free of dents, scratches, or deformation. The coatings (plating or painting) should be intact, with an aesthetically pleasing finish and excellent corrosion resistance.

Only frames that pass these tests are approved for the subsequent assembly.

FAQ

How to customize fire sprinkler heads?

Customizing fire sprinkler heads depends on your specific needs:

Minor Customization: If you only need small adjustments, like adding a brand or model number, you can choose a manufacturer’s existing design and make minor tweaks. This approach is cost-effective and quick, with minimal mold or sampling fees.

Full Custom Design: For more complex customization (e.g., unique deflector or trigger mechanisms), manufacturers can create a custom mold based on your detailed design. This option involves higher costs, longer lead times, and often requires a higher minimum order quantity (MOQ).

Design Assistance: If you don’t have a design, manufacturers can help create one for you. This requires finding a cooperative manufacturer and may involve more communication and higher initial costs.

What materials are sprinklers made of?

Most sprinkler heads are made from brass, with a smaller number made from stainless steel. Brass is the most common material due to its excellent durability, heat resistance, and corrosion resistance. It performs well in a wide range of environments, making it the preferred choice for most applications. On the other hand, stainless steel is used in more specialized environments, such as coastal areas or on ships, where corrosion resistance is particularly important due to the presence of saltwater.

What are the components of a standard sprinkler head?

A standard fire sprinkler head consists of four main components:

Frame: The body that houses all the internal components and provides structural support for the sprinkler head.

Heat-sensitive Element: This is usually a glass bulb or fusible link that reacts to heat. When the temperature exceeds a set threshold, the element breaks or melts, activating the sprinkler.

Deflector: A component that helps spread water in a uniform pattern over a wide area to effectively suppress the fire.

Sealing Assembly: This part seals the orifice (the water outlet) until the heat-sensitive element is triggered. Once activated, it releases the water to fight the fire.

What are the 4 types of sprinkler heads?

The four main types of fire sprinkler heads are:

Pendent Sprinkler: Mounted below the pipe, these sprinklers direct water downward towards the deflector, making them the most common type for standard ceiling installations in both commercial and residential settings.

Upright Sprinkler: Installed above the pipe, these sprinklers face upwards and spray water towards a deflector, which then directs it downward. They are ideal for spaces without ceilings or where pipes are mounted below beams.

Sidewall Sprinkler: Mounted on the wall, these sprinklers distribute water in a fan shape. They are commonly used in rooms like hotel rooms and corridors with horizontal ceilings.

Concealed Sprinkler: Hidden behind a decorative cover plate, these sprinklers stay flush with the ceiling. When activated, the cover falls off, exposing the sprinkler, making them a good choice for aesthetic environments.

How do fire sprinkler heads work?

Fire sprinkler heads are activated by heat, not smoke. Each sprinkler contains a heat-sensitive element, either a glass bulb filled with liquid or a fusible link. When the temperature in the area rises to a certain point—typically around 155°F (68°C)—the heat causes the glass bulb to break or the fusible link to melt. This triggers the release of water from the sprinkler. The deflector then spreads the water over the fire-affected area to suppress or extinguish the flames.

Conclusions

Producing fire sprinkler head frames involves a blend of precise design, careful material selection, and expert manufacturing techniques. Each step, from the initial drawings to final quality control, is critical to ensuring that the sprinkler heads function effectively and reliably during a fire. Understanding these processes helps anyone in the fire protection industry assess and identify the quality of sprinkler heads, ensuring that high-quality, compliant fire safety solutions are delivered. Whether you’re involved in customizing, sourcing, or selling sprinkler heads, knowing the complete production process guarantees that fire safety systems meet the highest standards of performance and reliability.

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