Understanding Corrosion in Water Pipelines: A Guide for Pipeline Designers

Last updated: January 22, 2020

## What Does Load Factor Mean?

Load factor is a ratio of the theoretical design strength to the maximum load expected in service. They are used in structural analysis to determine the design strength and compare it with maximum loads.

In aeronautics, load factor is the ratio of a specified load to the total weight of the plane; specified load may be expressed in terms of any of the following:

• Aerodynamic forces
• Inertia forces
• Ground reaction

Load factors are developed to help achieve the desired level of reliability of a structure based on probabilistic studies that take into account the load's originating cause, recurrence, distribution and static or dynamic nature.

Load factor can be derived from the load profile of the specific device or system of devices. In electricity, its value is always less than one because maximum demand is always more than average demand. A high load factor means power usage is relatively constant. Low load factor shows that occasionally a high demand is set. To service that peak, capacity sits idle for long periods, thereby imposing higher costs on the system.

Load factors can cause corrosion or growth of cracking in structures. Crack growth rates are influenced by environmental and load factors. They cause corrosion to grow in exposed areas, under paint, around fasteners, between layers of coating and inside structural components.

In structures, loads cause stresses, deformations and displacements. Assessment of their effects is carried out by the methods of structural analysis with the help of load factors. Excess load may cause structural failure, and hence such possibility should be either considered in the design.

Loads are increased by load factors to meet the requirement that design strength be higher than maximum loads. For example, in designing a staircase, a dead load factor may be 1.2 times the weight of the structure, and a live load factor may be 1.6 times the maximum expected live load. These two "factored loads" are combined (added) to determine the "required strength" of the staircase.