Monday, January 16, 2017

Retro Review: Halo HLC-1 Lighting Calculator

Retro Review:  Halo HLC-1 Lighting Calculator

HLC-1 Lighting Calculator
Years:  Unknown
Type:  4-Function, Lighting
Memory Registers: 1 (M)
Battery: A76

The Halo HCL-1 is a professional lighting calculator and a standard 4-function calculator. The standard 4-function calculator should be self-explanatory, let’s focus on the lighting part.

The HCL-1 is abundant on eBay, and make sure you get it with the foldout manual because (1) the manual is well written and (2) it explains the process in which pre-programmed calculations are completed.  I will show a short summary of some of the pre-calculations available below.

Trig table from the manual, something we don't see in calculator manuals

Did I mention that the manual contains a short table of sines and cosines?

US units are used (length is measured in feet).

Calculating Room Cavity Ratio:

Room Width in feet, [ RW ]
Rood Length in feet, [ RL ]
Room Cavity Height in feet, [ H ]

[ RCR ] calculates the Room Cavity Ratio

The HCL-1 assumes a rectangular room.  The formula:

RCR = (5 * H * (RW + RL)) / (RW * RL)

Footcandle Calculation

Coefficient of Utilization, between 0 and 1, [ CU ]
Number of lamp lumens, [ LL ]
Required footcandles, [ FC ]

Press [ CAL ].  If successful, a 0 appears in the display.
[ RCL ] [ NUM ]:  number of adjusted luminaries (lights)
[ RCL ] [ FC ]:  number of adjusted footcandles
[ RCL ] [ A ]:  area that is illuminated
[ RCL ] [ SPG ]:  fixture spacing in feet

I am thinking that this solves where to put ceiling lights on the ceiling in a grid, like in a school classroom or business office.

You can factor in the lamp lumen depreciation factor ( [ LLD ] ) AND luminaire dirt deprecation factor ( [ LDD ] ).

Final Verdict

I am glad to have the HLC 1 in my collection.  It is one of the most unique calculators ever made and was met with amusement when I posted a picture of it on my Instagram account.  Don’t lose the manual. 


This blog is property of Edward Shore, 2017

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