(HP-67/97) PF Calculation by DCPA Standard Method

[SlideRule]

An extract from PF Calculation by DCPA Standard Method, Defense Civil Preparedness Agency, DCPA01-76-C-0325, JAN 1978

INTRODUCTION
Although the "Standard Method" of calculating the protection factor of a shelter is well understood by qualified FSAs, it is seldom used in practice. Reasons for this are both numerous and controversial, but the fact remains that 1s is seldom used in practice.
The availability of programmable pocket type calculators in 1974-75 presented a new situation. It seemed, at that time, that the pocket computer might work in calculating the PF by the "Standard Method." Consequently, a feasibility study was undertaken to decide this issue.
The feasibility study was completed in December 1976 and a favorable report written and its recommendations were used as a basis for establishing the objectives of this project. In abbreviated form these objectives are:
1} Develop programs using "Standard Method" and broad enough to be used on either the Hewlett-Packard calculator or the Texas Instument calculator …
… It was decided to prepare the initial programs on the Hewlett-Packard Model 97 (desk top model) . These identical programs could also be used on the HP Model 67 (pocket type). These programs had to undergo significant changes before they would work on the Texas Instruments calculator. These changes were made for the TI Model SR52. About 30% more cards are required for the TI model than is necessary for the HP models. It is interesting to note at this writing that TI has produced a new Model 59 that will significantly reduce the necessary number of cards. Perhaps only one or two would be required.
The overall approach was to develop a single methodology that could be applied to either the TI or the HP calculators. The individual operation of the calculator would be different as is required by the uniqueness of the calculators. The "Standard Method's" functional equations were to be used, giving this aspect 100% accuracy. The "Standard Method" requires the use of charts and these charts had to be converted to equations that were workable on the programmed chip. It is in these equations that same accuracy is lost.

Quite a 99 page READ; enjoy!

BEST!
SlideRule

ps: really, enjoy!