Signs of the Times - September 2013 - (Page 30)

LIGHTING TECHNIQUES By Marcus Thielen Marcus Thielen is a physicist and lighting-industry consultant from Duisburg, Germany. Calculating Neon Sign Light Output Sign-code limitations necessitate accuracy. S ign permits, for maximum currently, may establish limits neon tube’s straight length to obtain its light output in lumens (which will give us our Result 4). Note, if parts are blocked out, they must be deducted from the length; if only half of the tube’s circumference is painted black, those lengths count only half. Officials typically want to know a planned sign’s maximum surface brightness to avoid eye irritations in traffic. The value is normally given in cd/m2, or in cd/sq. ft. A smaller-diameter tube emits light from a smaller surface, so the brightness is much higher. In short, we have to know the tube surface for each foot of length. To make unit conversions and constants short, multiply the tube diameter (in mm) by pi (3.14) and Photo credit Shane Ablon brightness and total light output. “Light pollution” has crept into zoning and sign-code jargon already. Consequently, more than ever, it’s often necessary to precisely estimate a sign’s luminous data. For box signs or banners lit with standard commercial lamps, data readily can be obtained from lamp-manufacturer catalogs. You only need to total it up. In contrast, neon signs, which are custom-made, present myriad variables. First, you must calculate total light output in lumens. This requires total tube length (in feet), the tube diameter and the transformer current. For multiple sections in different colors, individual calcu- lations are required for each diameter/color/current combination. Then, finally, they’re added up to obtain the total luminous flux. First, find the relevant color in Table 1, which gives the average light-output flux per foot for a 15mm tube diameter and a 30mA transformer (which is, effectively, 25mA, in operation). If the real tube diameter isn’t 15mm, and our transformer isn’t a magnetic, 30mA type, corrections are required. Look up a factor in Table 2. Multiply the number from Table 1 with the factor from Table 2, which gives us Result 3. Due to different phosphor characteristics and deviations from Table 1, errors can range from 10-15%. Result 3 is then multiplied by the Photo 1: Classic, open-face, clear-red neon in stainless-steel channel letters in Brooklyn, NY 30 SIGNS OF THE TIMES / SEPTEMBER 2013 /

Table of Contents for the Digital Edition of Signs of the Times - September 2013

Signs of the Times - September 2013
ST Update
Technology Update
Who Uses the Phone Book?
Vinyl Apps
Strictly Commercial
Lighting Techniques
The Moving Message
Technology Review - DGS 3D POP store system
Technology Review - KIP C7800 poster printer
Design Matters
New Products
When the Cheering Starts
Enter the ST Intl. Sign Contest!
Starting at the Bottom
LED Lamps for Box/Cabinet Signs
The Aria’s 260-ft. Pylon Sign
Industry News
Advertising index
Editorially speaking

Signs of the Times - September 2013