Live load. Dead load. Governing code? What’s the difference between these structural design terms in regards to building design loads and how can they differ from structure to structure?
Insurance claim adjusters rejoice!
Here’s the scoop on all of the above terms and what you need to know before investigating your next structural design claim.
Dead loads: refer to loads that typically don’t change over time, such as the weights of materials and components of the structure itself (the framing, the flooring material, roofing material, etc.),and the weights of fixed service equipment (plumbing, HVAC, etc.).
Live loads: refer to loads that do, or can, change over time, such as people walking around a building (occupancy) or movable objects such as a flower pot on a deck. In addition to live loads, what is known as environmental loads are loads that are created naturally by the environment and include wind, snow, seismic, and lateral soil pressures.
What about building codes?
In terms of structural issues, building codes refer to a set of International Codes developed by the International Code Council (ICC) which umbrellas the following code sets: the International Building Code (IBC), the International Residential Code For One- and Two-Family Dwellings (IRC), the International Plumbing Code (IPC), and the International Mechanical Code (IMC).
As far as structural claims go, make it a habit to first check with the local building department where the building in question is located in order to determine which code set is enforced.
It is equally important to check with the building department, as they may also issue specific requirements pertaining to the environmental loads.
Governing code: encompasses the building code that each building department enforces, as well as any specific requirements enforced in a given municipality (such as environmental loads). Most often, governing codes include amendments to the building code.
In addition to determining which building code set is applicable to your specific claim, the following building design factors also need close consideration:
- The risk, or occupancy category: refers to the type of habitation the structure is being used for to determine the risk to human life if the structure were to fail in some way. For example, a structure that is used to store hay compared to a structure that is used as an elementary school would be in significantly different risk categories, as an elementary school constains more elements of safety for human life.
- Dead load factor: which takes into consideration the types of materials used to build the structure and the associated material weights. While most single family homes are made out of wood framing materials, commercial structures can vary from wood, to metal, to concrete.
- The design of live loads: what is the purpose and use of the structure? What are the live load requirements for the structure? For example, a single family home, a restaurant, and a stadium would all have different live load requirements. Moreover, the IBC lists live load requirements for differing rooms within a structure. For example, a library has a higher requirement for live load in a room where books are stacked versus a room that’s designated just for reading, because rows and rows of books weigh a lot more than a few people each reading one book while sitting on some chairs.
Want more? Read the full article, published in the September 12, 2012 online edition of PLRB – Test Your Claims Knowledge.
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