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<DIV dir=ltr align=left><FONT face=Arial size=2><SPAN
class=885354512-30062009>Building-Sim users,</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial size=2><SPAN
class=885354512-30062009></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial size=2><SPAN
class=885354512-30062009>Perhaps somebody could shed some light on this issue
for me.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial size=2>In 90.1 Appendix G, Table G3.1,
Section 6.f. states that credit can be taken in the proposed building for
automatic controls due to daylight utilization. However:</FONT></DIV>
<UL dir=ltr>
<LI>
<DIV align=left><FONT face=Arial><FONT size=2><SPAN
class=885354512-30062009>In </SPAN>order to know how much of an effect
daylight should have on the power used, a target luminance/lux level is
required. If this <SPAN class=835435412-30062009>target is met </SPAN>by
daylight alone, the lighting consumption would drop to 0 (except for emergency
lighting). Where daylight falls between 0 and the target lux level, lighting
power can be scaled linearly.</FONT></FONT></DIV></LI></UL>
<UL dir=ltr>
<LI>
<DIV align=left><FONT face=Arial size=2>The documentation gives no target lux
levels and they cannot be derived from the baseline lighting power densities
(from 90.1 Sections 9.5.1/9.6.1) without knowing the efficiencies associated
with these values.</FONT></DIV></LI></UL>
<UL dir=ltr>
<LI>
<DIV align=left><FONT face=Arial><FONT size=2>The only related luminance
levels available are from the IESNA Lighting Handbook but these levels do not
seem to sensibly correlate with the power densities of 90.1 Sections
9.5.1/9.6.1. Take, for example, <SPAN
class=885354512-30062009>a</SPAN> drafting office. The IESNA Lighting
Handbook Section 10, Quality of the Visual Environment, suggests a lighting
level of around 100fc (1076 lux). <SPAN
class=885354512-30062009>Achieving</SPAN> this 100 fc with an LPD of 1.1W/ft²
(11.83W/m²), i.e. that quoted for an Open Plan Office, requires a lamp with an
efficiency of approximately 91 lumens/watt. Using the same Lighting
Power Density, and illuminance of 30fc for simple office tasks, we require
lights that produce 27 lumens/watt.<SPAN class=835435412-30062009> This
gives us two spaces that are classified identically, but are subject to
massively different limitations when it comes to selecting
lamps.</SPAN></FONT></FONT></DIV></LI></UL>
<DIV><FONT face=Arial size=2>Could somebody please provide some clarification on
whether it is wise to assume these lux levels while performing a Building
Performance Method simulation, bearing in mind that it could affect results in
an unfavourable way if lux level is overestimated (as LPD will be constant in
the baseline buildings).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial size=2>Regards,</FONT></DIV></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><SPAN class=835435412-30062009><FONT face=Arial size=2>Jonathan
Catterall</FONT></SPAN></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
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<P class=MsoNormal><B><SPAN
style="COLOR: #333333; FONT-FAMILY: Arial">Jonathan <SPAN
class=SpellE>Catterall</SPAN><BR></SPAN></B><SPAN class=SpellE><SPAN
style="FONT-SIZE: 8pt; COLOR: #999999; FONT-FAMILY: Arial">BSc</SPAN></SPAN><SPAN
style="FONT-SIZE: 8pt; COLOR: #999999; FONT-FAMILY: Arial"> (<SPAN
class=SpellE>Hons</SPAN>) <SPAN class=SpellE>Dunelm</SPAN>, <SPAN
class=SpellE>MSc</SPAN><BR>Software Developer</SPAN><B><SPAN
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