Custom Search
/* Variable definitions ==================== */ body { background:#123; margin:0; text-align:center; line-height: 1.5em; font: x-small Trebuchet MS, Verdana, Arial, Sans-serif; color:#333333; font-size/* */:/**/small; font-size: /**/small; } /* Page Structure ----------------------------------------------- */ /* The images which help create rounded corners depend on the following widths and measurements. If you want to change these measurements, the images will also need to change. */ #outer-wrapper { width:740px; margin:0 auto; text-align:left; font: normal normal 100% 'Trebuchet MS',Verdana,Arial,Sans-serif; } #main-wrap1 { width:485px; float:left; background:#eeeecc url("http://www1.blogblog.com/rounders3/corners_main_bot.gif") no-repeat left bottom; margin:15px 0 0; padding:0 0 10px; color:#333333; font-size:97%; line-height:1.5em; word-wrap: break-word; /* fix for long text breaking sidebar float in IE */ overflow: hidden; /* fix for long non-text content breaking IE sidebar float */ } #main-wrap2 { float:left; width:100%; background:url("http://www1.blogblog.com/rounders3/corners_main_top.gif") no-repeat left top; padding:10px 0 0; } #main { background:url("http://www.blogblog.com/rounders3/rails_main.gif") repeat-y left; padding:0; width:485px; } #sidebar-wrap { width:240px; float:right; margin:15px 0 0; font-size:97%; line-height:1.5em; word-wrap: break-word; /* fix for long text breaking sidebar float in IE */ overflow: hidden; /* fix for long non-text content breaking IE sidebar float */ } .main .widget { margin-top: 4px; width: 468px; padding: 0 13px; } .main .Blog { margin: 0; padding: 0; width: 484px; } /* Links ----------------------------------------------- */ a:link { color: #445566; } a:visited { color: #223344; } a:hover { color: #223344; } a img { border-width:0; } /* Blog Header ----------------------------------------------- */ #header-wrapper { background:#335577 url("http://www2.blogblog.com/rounders3/corners_cap_top.gif") no-repeat left top; margin-top:22px; margin-right:0; margin-bottom:0; margin-left:0; padding-top:8px; padding-right:0; padding-bottom:0; padding-left:0; color:#ffffff; } #header { background:url("http://www.blogblog.com/rounders3/corners_cap_bot.gif") no-repeat left bottom; padding:0 15px 8px; } #header h1 { margin:0; padding:10px 30px 5px; line-height:1.2em; font: normal bold 200% 'Trebuchet MS',Verdana,Arial,Sans-serif; } #header a, #header a:visited { text-decoration:none; color: #ffffff; } #header .description { margin:0; padding:5px 30px 10px; line-height:1.5em; font: normal normal 100% 'Trebuchet MS',Verdana,Arial,Sans-serif; } /* Posts ----------------------------------------------- */ h2.date-header { margin-top:0; margin-right:28px; margin-bottom:0; margin-left:43px; font-size:85%; line-height:2em; text-transform:uppercase; letter-spacing:.2em; color:#558866; } .post { margin:.3em 0 25px; padding:0 13px; border:1px dotted #bbbbbb; border-width:1px 0; } .post h3 { margin:0; line-height:1.5em; background:url("http://www2.blogblog.com/rounders3/icon_arrow.gif") no-repeat 10px .5em; display:block; border:1px dotted #bbbbbb; border-width:0 1px 1px; padding-top:2px; padding-right:14px; padding-bottom:2px; padding-left:29px; color: #333333; font: normal bold 135% 'Trebuchet MS',Verdana,Arial,Sans-serif; } .post h3 a, .post h3 a:visited { text-decoration:none; color: #333333; } a.title-link:hover { background-color: #bbbbbb; color: #333333; } .post-body { border:1px dotted #bbbbbb; border-width:0 1px 1px; border-bottom-color:#eeeecc; padding-top:10px; padding-right:14px; padding-bottom:1px; padding-left:29px; } html>body .post-body { border-bottom-width:0; } .post-body { margin:0 0 .75em; } .post-body blockquote { line-height:1.3em; } .post-footer { background: #ffffff; margin:0; padding-top:2px; padding-right:14px; padding-bottom:2px; padding-left:29px; border:1px dotted #bbbbbb; border-width:1px; font-size:100%; line-height:1.5em; color: #666666; } /* The first line of the post footer might only have floated text, so we need to give it a height. The height comes from the post-footer line-height */ .post-footer-line-1 { min-height:1.5em; _height:1.5em; } .post-footer p { margin: 0; } html>body .post-footer { border-bottom-color:transparent; } .uncustomized-post-template .post-footer { text-align: right; } .uncustomized-post-template .post-author, .uncustomized-post-template .post-timestamp { display: block; float: left; text-align:left; margin-right: 4px; } .post-footer a { color: #456; } .post-footer a:hover { color: #234; } a.comment-link { /* IE5.0/Win doesn't apply padding to inline elements, so we hide these two declarations from it */ background/* */:/**/url("http://www.blogblog.com/rounders/icon_comment_left.gif") no-repeat left 45%; padding-left:14px; } html>body a.comment-link { /* Respecified, for IE5/Mac's benefit */ background:url("http://www.blogblog.com/rounders3/icon_comment_left.gif") no-repeat left 45%; padding-left:14px; } .post img { margin-top:0; margin-right:0; margin-bottom:5px; margin-left:0; padding:4px; border:1px solid #bbbbbb; } blockquote { margin:.75em 0; border:1px dotted #bbbbbb; border-width:1px 0; padding:5px 15px; color: #558866; } .post blockquote p { margin:.5em 0; } #blog-pager-newer-link { float: left; margin-left: 13px; } #blog-pager-older-link { float: right; margin-right: 13px; } #blog-pager { text-align: center; } .feed-links { clear: both; line-height: 2.5em; margin-left: 13px; } /* Comments ----------------------------------------------- */ #comments { margin:-25px 13px 0; border:1px dotted #bbbbbb; border-width:0 1px 1px; padding-top:20px; padding-right:0; padding-bottom:15px; padding-left:0; } #comments h4 { margin:0 0 10px; padding-top:0; padding-right:14px; padding-bottom:2px; padding-left:29px; border-bottom:1px dotted #bbbbbb; font-size:120%; line-height:1.4em; color:#333333; } #comments-block { margin-top:0; margin-right:15px; margin-bottom:0; margin-left:9px; } .comment-author { background:url("http://www.blogblog.com/rounders3/icon_comment_left.gif") no-repeat 2px .3em; margin:.5em 0; padding-top:0; padding-right:0; padding-bottom:0; padding-left:20px; font-weight:bold; } .comment-body { margin:0 0 1.25em; padding-top:0; padding-right:0; padding-bottom:0; padding-left:20px; } .comment-body p { margin:0 0 .5em; } .comment-footer { margin:0 0 .5em; padding-top:0; padding-right:0; padding-bottom:.75em; padding-left:20px; } .comment-footer a:link { color: #333; } .deleted-comment { font-style:italic; color:gray; } .comment-form { padding-left:20px; padding-right:5px; } #comments .comment-form h4 { padding-left:0px; } /* Profile ----------------------------------------------- */ .profile-img { float: left; margin-top: 5px; margin-right: 5px; margin-bottom: 5px; margin-left: 0; border: 4px solid #ffffff; } .profile-datablock { margin-top:0; margin-right:15px; margin-bottom:.5em; margin-left:0; padding-top:8px; } .profile-link { background:url("http://www.blogblog.com/rounders3/icon_profile_left.gif") no-repeat left .1em; padding-left:15px; font-weight:bold; } .profile-textblock { clear: both; margin: 0; } .sidebar .clear, .main .widget .clear { clear: both; } #sidebartop-wrap { background:#558866 url("http://www.blogblog.com/rounders3/corners_prof_bot.gif") no-repeat left bottom; margin:0px 0px 15px; padding:0px 0px 10px; color:#ffffff; } #sidebartop-wrap2 { background:url("http://www2.blogblog.com/rounders3/corners_prof_top.gif") no-repeat left top; padding: 10px 0 0; margin:0; border-width:0; } #sidebartop h2 { line-height:1.5em; color:#ffffff; border-bottom: 1px dotted #ffffff; font: normal bold 100% 'Trebuchet MS',Verdana,Arial,Sans-serif; margin-bottom: 0.5em; } #sidebartop a { color: #ffffff; } #sidebartop a:hover { color: #ffffff; } #sidebartop a:visited { color: #ffffff; } #sidebar a { color: #99ddbb; } #sidebar a:hover, #sidebar a:visited { color: #ffffff; } /* Sidebar Boxes ----------------------------------------------- */ .sidebar .widget { margin:.5em 13px 1.25em; padding:0 0px; } .widget-content { margin-top: 0.5em; } #sidebarbottom-wrap1 { background:#335577 url("http://www.blogblog.com/rounders3/corners_side_top.gif") no-repeat left top; margin:0 0 15px; padding:10px 0 0; color: #ffffff; } #sidebarbottom-wrap2 { background:url("http://www1.blogblog.com/rounders3/corners_side_bot.gif") no-repeat left bottom; padding:0 0 8px; } .sidebar h2 { margin-top:0; margin-right:0; margin-bottom:.5em; margin-left:0; padding:0 0 .2em; line-height:1.5em; font:normal bold 100% 'Trebuchet MS',Verdana,Arial,Sans-serif; } .sidebar ul { list-style:none; margin:0 0 1.25em; padding:0; } .sidebar ul li { background:url("http://www2.blogblog.com/rounders3/icon_arrow_sm.gif") no-repeat 2px .25em; margin:0; padding-top:0; padding-right:0; padding-bottom:3px; padding-left:16px; margin-bottom:3px; border-bottom:1px dotted #bbbbbb; line-height:1.4em; } .sidebar p { margin:0 0 .6em; } #sidebar h2 { color: #aabbcc; border-bottom: 1px dotted #aabbcc; } /* Footer ----------------------------------------------- */ #footer-wrap1 { clear:both; margin:0 0 10px; padding:15px 0 0; } #footer-wrap2 { background:#335577 url("http://www2.blogblog.com/rounders3/corners_cap_top.gif") no-repeat left top; color:#ffffff; } #footer { background:url("http://www.blogblog.com/rounders3/corners_cap_bot.gif") no-repeat left bottom; padding:8px 15px; } #footer hr {display:none;} #footer p {margin:0;} #footer a {color:#ffffff;} #footer .widget-content { margin:0; } /** Page structure tweaks for layout editor wireframe */ body#layout #main-wrap1, body#layout #sidebar-wrap, body#layout #header-wrapper { margin-top: 0; } body#layout #header, body#layout #header-wrapper, body#layout #outer-wrapper { margin-left:0, margin-right: 0; padding: 0; } body#layout #outer-wrapper { width: 730px; } body#layout #footer-wrap1 { padding-top: 0; } -->

Tuesday, March 17, 2009

Lighting Design The Lumen Method Explained





When Designing and calculating lighting design for internal areas, the quickest system to use is the lumen method. I have used this method for many years and the installed results were always accurate to the designed and required lighting level.





In design it is important to keep the balance between the minimum requirements as called up by relevant standards and by local authorities and balance it against the cost of installed and running the lighting for the development, if you over design the client wont thank you for an non green design and if you under design you could have serious problems with dark areas, or dim lighting.

By following this guide you will over come most of this pit falls and reach the required balance.

Step One.
Take the measurement of the room you are designing for in Meters and find the area. Then you must determine the working plane, if the room is to be an office then this will be at desk height (0.75m) from the floor, if the room is to be an office then this will be zero.

Take the height from the floor to the ceiling and take the height of the working plane from it.

Example: you have a room with the following.
length 23.8m
Width 14.5m
gives and area of 345.1m

the room is a function room so we take the working plane as 0.75m
The mounting height is 3m (floor to ceiling) - 0.75m gives 2.25m

use the following formula to calculate the room index.

Room index (RI) = A/h(a+b) 345.1/2.25(23.8+14.5) = 4.0

Step 2.
When the lights are installed at first they will give out 100% of there illumination but over time dust and grime will reduce this value so we must make allowances for that now. If the maintenance on the lighting is regular then a high value can be attributed, if the maintenance factor is unknown at design stage then a MF of 0.85 is acceptable.


Step 3.
When designing lighting systems you have to select exact fittings with known values to work to, So select a lighting catalogue that contains detailed data on the fitting and lamp types available and not catalogues that a focused towards architects and interior designers as these are generally just full of pretty pictures, I would recommend using Thorn or Philips are they have a good range of medium to high quality fittings. I would also recommend visiting there web sites to check for updates to there selection or for further technical information.

For our calculation example above the Coefficient of Utilisation is 0.46, which was obtained from the manufactuers catalogue with the use of the RI and the reflectances. For office areas or hotels expect a high reflectance values which are based on the colour of the ceilings walls and floor. Areas such as stores or back of house areas would be expected to have lower relectances values and will have an effect on the coefficient of utilisation fugure you get.

Step 4.
Note the number of lamps (tubes, bulbs) in the selected fitting and the luminour flux per tube, this figure will come from the manufacturers catalogue. Also note the wattage per lamp.

In the case of our example from above the following values resulted:

Luminour Flux per tube 20000

No of Tubes per Fitting 1

Watts per Tube 250

Step 5.
It is important to know for the application the required lux levels to be achieved in the room, for calculations in the UK we refer to the British Standard for minimum levels. For our example the require illumination value was 250.

Step 6.

Riv = Required Illumination Value
A = Area
MF = Maintenance Factor
CU = Coefficient of Utilisation
L = Luminous Flux per tube
T = No of Tubes

Fixtures Required = RIV x A
MF x CU x L x T

250 x 345.1 =
1 x 0.46 x 20000 x 1

86275 = 11.03
7820

11.03 is rounded off to 11 No. fixtures required to meet the lux levels in this room with this type of fitting and this type of lamp installed.

For asthehics this figure was increase to 12 No fittings with 4 rows of 3 No fittings installed.
We use the following Formula to determine the lux output achieved for 12 No fittings installed.

where F = No of Fitting Installed.

Average Illuminance =

F x CU x MF x L x T
A

12 x 0.46 x 0.85 x 20000 x 1 = 271.9 Lux

345.1

There are lighting software packages available that can calculate far more complex rooms and areas which I will discuss in a latter issue.

If you have any questions or queries please leave a comment.

http://www.engineerstoolbox.blogspot.com/

1 comment:

  1. My professional edition of Pro-E won't open files that were created in the student edition of the software. I have several CAD drawings that I created at school and now I can't use them at home. Is there a workaround/hack to this BS from Dassault?.

    Solidworks Training

    ReplyDelete