The weight limits for hangers used in conduit and pipe installations are determined by several factors, including the type of hanger, the material of the conduit or pipe, and the installation environment. Generally, hangers must be capable of supporting the weight of the conduit or pipe, as well as any additional loads such as insulation or contents within the pipe.
1. **Material and Type of Hanger**: Hangers are typically made from materials like steel, stainless steel, or plastic. Steel hangers are commonly used for their strength and durability. The type of hanger (e.g., clevis hangers, split ring hangers, or trapeze hangers) also affects the weight limit, with each type designed for specific applications and load capacities.
2. **Conduit or Pipe Material**: The weight of the conduit or pipe itself is a critical factor. For example, steel pipes are heavier than PVC pipes, requiring hangers with higher weight capacities.
3. **Load Ratings**: Manufacturers provide load ratings for hangers, which indicate the maximum weight the hanger can support. These ratings are based on standardized tests and are often listed in product specifications or catalogs.
4. **Installation Environment**: Environmental factors such as temperature, humidity, and exposure to chemicals can affect the performance of hangers. In corrosive environments, stainless steel or specially coated hangers may be necessary to maintain structural integrity.
5. **Code and Standards Compliance**: Installation must comply with relevant codes and standards, such as the National Electrical Code (NEC) or the International Building Code (IBC), which may specify minimum requirements for hanger spacing and load capacity.
In summary, the weight limits for hangers in conduit and pipe installations depend on the hanger type, material, load ratings, and environmental conditions, and must comply with applicable codes and standards.