Lighting Design + Application • October 2003 - Illuminating ...

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DESIGN TRENDSare often misleading, requiring that additional performanceverification be provided.• Specify Luminaires with Expertly ConceivedMating Mechanisms. Even if a fixture is appropriatelycertified for an application, the housing must interface virtuallyseamlessly with the ceiling to achieve the requiredlevel of in-situ performance. Consider that the installermust mate a milled piece of flat metal to an inherentlyuneven gypsum ceiling (gypsum being the most commonceiling material in clean room construction). The mosteffective systems employ multiple springs to push thehousing firmly against the ceiling – a recently developedapproach that has consistently proven superior to othertechniques in use.• Create the Best Scheme Possible for Mixed-Task Environments. With the trend towards cleanrooms that combine wet lab and computational functionsin the same area, some people need 60-80 fc at 36 in. AFFwhile others immediately adjacent to them may needmuch lower light levels for computer work at 30 in. AFF.And, the presence of computers combined with the growingrecognition of both discomfort and disability glaremeans that high-brightness fixtures are no longer appropriate.As a result, highly informed selection of fixturetypes and expert layout are far more important in labs ofall types than ever before. This is an area in which the professionallighting consultant can truly excel, choosing froma menu of ambient and task/ambient techniques that canbe expertly applied on a project-specific basis.• Write a Solid, Performance-Based Spec. As withthe lighting performance specs that are an integral part ofa commercial lighting professional’s stock-in-trade, the keyto ensuring the environmental integrity of a clean room isa product performance specification consistent withacknowledged standards and criteria... with the manufacturer’sstated product performance confirmed throughindependent testing.Fixture PerformanceHere’s a brief overview of some of the most criticalmechanical performance criteria for clean room applications.The fixture:1) Shall Not Leak. A well-accepted leakage standardcomes from the International Electromechanical Commission’sDegrees of Protection Provided by Luminaires. TheIEC’s Ingress Protection Standard appropriate to a largenumber of clean room applications is IP65. (The first digit“6” rates ingress protection from solid objects, while thesecond digit “5” rates ingress protection from water.)A fixture with an IP65 rating is essentially dustproof andwaterproof, and is therefore appropriate for a large numberof clean room applications. Testing and confirmationare typically received from U.L.2) Shall Not Introduce Corrosion or Toxicity. TheNational Sanitation Foundation International’s (NSF)Special Equipment or Devices standard is widely acceptedin this area. The Splash/Non Food Zone and Food Zone/NonContact criteria both state that materials and design mustassure that neither corrosion nor toxicity can be introducedby the fixture, and are very specific about materialselection, design and fabrication techniques. Testing andconfirmation are available directly by NSF.3) Shall Be Easily Cleaned. The standard, criteria andtesting confirmation are the same as #2 (above).4) Shall Be Safe in Class I, Division 2; Class II,Division 2 and Simultaneous Hazardous LocationsApplications. The accepted standard for this requirementcomes from the National Fire Protection Association(70-2002). Class I, Division 2 applies to flammable gasses,while Class II, Division 2 applies to explosive dusts. (TheDivision 2 classification denotes that the hazardous materialis present only in abnormal conditions, such as accidentalspillage. Intentional open presence of hazardousmaterials would be classified as Division 1.)A New Opportunity For a New EraThe emergence of new scientific technologies has createdan increasing and evolving demand for clean roomsand a concurrent need for more effective clean room lighting.As a result of the slow response by most fixture manufacturersto respond to the challenge, architects and engineershave either had to settle for inappropriatelydesigned and constructed lighting or spend inordinateamounts of time and budget researching potential solutionsand specifying custom fixtures.Now that innovative fixtures that successfully addressmany of the most critical clean room requirements havecome onto the market, the gauntlet is being passed to thelighting community, offering an opportunity to improvethe performance and integrity of scientific facilities thatare sure to have a major impact on our world.By applying the same rigorous approach to clean roomlighting design and fixture performance and verificationstandards that have become expected for the lighting ofcomputer-equipped offices, lighting specifiers can providesubstantial benefits in lighting performance, operationalsafety and clean room economics while creating newopportunities for themselves and the lighting industry as awhole.About the Authors: JamesPark, AIA, is an associate withMBT Architecture in San Francisco,a leader in the design ofscience and technology facilities.He has 15 years experiencedesigning technically complexprojects for the R&D, biopharmaceuticaland advanced technology industries.Thomas Ramsey, AIA, is a principal of RPR Architectsin Oakland, CA, a firm well known for its work ontechnology-intensive projects. He has had specializedtraining in cGMP and cGLP procedures for the designof biotech manufacturing and laboratory facilities.George Ryder has been highly involved in the designof lighting systems for clean room and laboratoryapplications for over 15 years. He is a vice president of Kenall ManufacturingCompany in Gurnee, IL.. . . . . . . . . . . . . . . . . . . November . . . . . 2003 . . . LD+A . . . . 66. . www.iesna.org. . . . . . . . . . . . . . . . . . . . . . . . . . . . .