PHI™ is the unit of measure for pole strength and serviceability developed by Thor Poletest. PHI™ is a normalised indication of a wood pole’s integrity. This is done by comparing the Thor Poletest assessment of the pole to a new pole of the same type and size.

Fibre strength varies from species to species as much as it does from pole to pole. Aggregated fibre strengths values are used to conservatively predict strength. With the generation of PHI™, the contribution of the associated fibre strength value is minimised. The PHI™ unit of measurement is fundamentally comparing the condition of the pole against an idealised pole of the same size as new. The same fibre strength factor is used for both calculations, it is a comparative exercise and assumes the original pole was specified correctly for its application.

Small-diameter wood poles, particularly sourced from Eucalyptus and Pinus species, are being utilised for wood power poles. While these poles possess adequate mechanical properties, it's important to note that their characteristics may differ from poles sourced from fully matured larger diameter trees.

As a complement to the primary unit of measure of condition (PHI™), RSV% is available as a supplementary data value and is dependent on license type selected. RSV is a calculated value to predict the remaining strength of a pole compared to what it was when it was new. Ie: if a pole was rated to 10kN when it was new and has an RSV score of 45%, it would be suitable for a 4.5kN load.

It considers wood type, age and maturity. Note; If no pole age is available, the pole age is assumed to be 50 years.

RSV% values need to be considered with some knowledge of the pole history and original design parameters. Thresholds should be established based on the Factors of Safety (FOS) your network uses for design and operation

Environmental stressors such as drought, disease, insect infestation, and physical damage can impact the quality of wood. Trees subjected to stressors may produce wood with irregularities or defects that affect its strength and durability.