Theatre Design & Technology - Fall 1993 - 40

TEST RESULTS
Brodeur res red ren common monirors
used wirh l\lacinrosh compurers. The
re,ulrs are di,rurbing. ,\Iosr of rhe high
frequencv r.ldi.Hion remains wirhin rhe
ca,e, bur rhe ,'en' low and exrremelv low
frequencie (\;LF Jnd ELF) r<:;dil~'
escape from rhe from. ide~ and back of
rhe unir. Ar .1 disrance of four inche
from rhe screen, emissions were ren
rime, a high (22.- mG) as rhose linked
wirh cancer in children (2 mG). Anal~'-
si, of rhe AppleColor RG B ~loniror ar a
fourinch disrance produced rhe following resulrs: 3'.' mG from rhe back of
rhe compurer, 70.9 mG from rhe righr
and 67.8 mG from rhe lefr side. Ar J.?
inches, rhe e1enromagneric radiarion
ranged from a low of J. 11 milligauss ar
rhe from of rhe screen ro a high of 15.86
milligauss ar rhe side of a color. high resolurion moniror. The readings drop off
ar abour rhree feer ro 1.1 mG or below.
Brodeur found rhar only ar a disrance of
28 inche, (:Hm's lengrh) was ir sensible
ro sir ar rhe from of rhe screen. Four feer
was rhe recommended disrance from rhe
sides and back. Your neighbor in a
design lab may be exposed ro more of
rhe harmful radiarion from rhe sides and
back of "our compurer rhan "ou are
from rhe screen irself.
In anorher resr, US 'eWJ tllld \'(Iorld
Reporr measured the srrengrh of magneric fields emirred by 30 monirors in rheir
offices, including IBi\I, Zenirh, NEC,
and orhers. Ar a disrance of 24 inches
from rhe from screen, rhe fields from 28
of rhe 30 monirors fell below rwo mG.
The srudy showed rhar monochrome
monirors had uniformly weaker fields
rhan rhe color PC monirors, dipping
below rwo mG only 18 inches away
from rhe screen."
You can conducr vour own resr.
There ,He several models of elecrric field
measuremem devices and ELF ~Ield survel' meters rhar you can rem or bu~'. everal companies have device available:u
a wide range of prices from S I 00 remals
up ro more rhan 1,000 for purchase. A
less expensive alrernati"e is ro conran
the el1l'ironmenral healrh .1nd safery
dep.lrllnelH of your comp.1ny or universiry ro measure rhe elecrromagneric field
r.ldiarion from l'Our rerminal.

REMEDIES
* lI'eden and Canad,l have set indusrry
srandards for VLF emissions from VDTs
and terminal do exisr rhar comply wirh
rhose .'landards. You can buy a moniror
wirh lower-rhan average emissions.
38

1993 FAll

TD&T

I\lan)' of rhe major manufacrurers,
including IBi\1 and DEC, have begun ro
sell monirors rhar meer rhe ,randard ser
by an advisorv board ro rhe Swedish
govern men r - \'LF m agneric field
srrengrh of 0.5 mG or less measured 20
inches from rhe from screen. However,
according ro Brodeur. ir is nor clear
wherher rhese terminals miligare rhe
hazards of ELF radiarion emissions.
LCDs (liquid crysral displal'S) don'r generare even a rrace of a ficld. There arc
LCD monirors available rhar lI'ork wirh
mosr PCs and 1\ lacs. '

THOSE OF US IN THE
THEATRICAL PROFESSIONS
WHO USE COMPUTERS OR
IGHTING CONSOLES WITH
VIDEO DISPLAYS SHOULD
BE CONCERNED ABOUT THE
POSSIBLE HAR FUL
EFFECTS OF VDT RADIATION
AND KNOW HOW TO
MINIMIZE THE RISK OF
EXPOSURE.
Bew:ue of false remedies like anrirad iarion screens. 1\ lost of rhem block
electric fields. nor rhe more harmful
magneric fields. Even rhe lead apron you
wear when gerring demal X-ravs won'r
prorecr you from DT radi:uion, ince
ELF can easily penerrare lead and concrere. The on Iv filrer rhar will work is
one made from a mJrerialwirh magnetic properries. Dimming the display
won't help eirher, since ir does nor affecr
the magnetic flcld.
Children and t'ilHendo players like
ro get close to screens. In university
computer labs it is rare to find compurer, a much as tWO ro three feet aparr.
The same goe for CA 0 and design lab
in rhearre deparrmelHs and professional
rlrms. If you work regularly ar a compurer, you should rry to stav at least
arm's lengrh from rhe screen and design
your lab in such a way rhar maimains ar

leasr rour feet of space berween rhe u er
and orher compurers. Do nor ler anyone
sit roo close ro rhe sides or back of rhe
"ideo rerminal. Insist rhar the manufacturer provides information about rhe
magnirude of e1ecrromagneric fields
emirted by ~'our video display rerminal.
Even'one should be informed of the
porenrial health hazards of computer
use, especiall~' anyone who is pregnanr.

RESPONSE
A Few companies, mosr norablv Apple,
suPPOrt rhe developmenr of indusrrl'wide safery standards ror elecrromagneric emissions from com purer screens. In
rhe meantime. there is a disrincr lack of
prorective guidelines and there is disagreemenr in rhe scienrific communiry
:lbour how elecrromagnetic radiarion
affecrs rhe body. l everr heless, rhere are
some communiries thar have implemented policies For compurer use. In
May 1989, Suffolk Counry, New York
regula red rhe use of VDTs for permanenr employees working on rhem conrinuouslv for more than 26 hours a
week. Twemy srares considered 41 proposals ro regulate the use of video display rerminals in 1991, up from 11
srares in 1990, according to rhe Celller
for Office Technology.

CONCLUSION
\X1orking ar rhe computer may cause
R Is (repetitive srrain injuries), and
rhere are other job-related working condirions rhar induce suess, spinal pain,
and eyestrain. However, rhere may be
more serious healrh problems in rhe
future if we don't firsr idenri~' and then
rake correcrive measure concerning
elecrromagneric field radiarion.
~
Parrick M, Finelli, PhD, iJ tI proftHor of
thetltrl' tit Ulli/lerJi~J' ofSouth Floridtl tlnd
the TD6- T editorfor colllputen.
Endnotes
I

!'Jul Bn)Je..'tlr. Cttrrr'Uh (~I Dr.ll:': Porn'r Lmc'i, COmpltla /;',111111.1L*. m" th,· .4.1umr! w Cour l f Iht'Ir rhrt".ll
(f)

llmr flr-.dlh

t ~C\\ York. ='Y: Simon

&: SChll~tc:r.

1'>8.)1.
P.lu! Brotil'u!'". .. rhl:' H.ll.lrd" of EkurolllJgnclh..
hdJ~." Iht'SOL }orA·c'T. ~() June 1989; 59-(ll .

3 PJul BroJt.'ur. . rhL' \1.1gncIi(-FidJ \lcnJLc.. :floflrM,

~Thl" 11.1/.IfJ'I

lorA'a.

t',

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July 1<)')0: ..:on.. r story.
1(1 JUll!,.'

.\'t'1l'1.l1ul

of Ul'ClrOn1Jgfll:tic l:jl·IJs:· Thr:

,\'rU

I 98 l ): 59-(lI .

\torld R"/,orf, 10

~t.'p{elllhcr 19\)0: So).

() C'; Stll'J ,lilt! \rorltl Rqorr. 10 Sr.:ph:mba 19lJO: 8;;.
.... "~crCl:n re\I," l1u tV,lllon, Augu.:->I 2-rSI,.·plcmbcr J.
1990,201.
S L'.\ 'vt'll'$ ,IUd \r(lr/d /(t'/,orr. 10 Septt'mber 1\)90: 8).

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Table of Contents for the Digital Edition of Theatre Design & Technology - Fall 1993