Presentation on theme: "SSL Cleanroom Training September 6, 2011 Jeremy McCauley, PFP CCE & PPE Mars Atmosphere and Volatile EvolutioN (MAVEN) Mission."— Presentation transcript:
SSL Cleanroom Training September 6, 2011 Jeremy McCauley, PFP CCE & PPE Mars Atmosphere and Volatile EvolutioN (MAVEN) Mission
2 SSL Cleanroom Training, September 6, 2011 Training Objectives Provide Understanding of: –Need for cleanrooms –Cleanroom Classifications –Sources of Contamination –Human Contamination –Cleanroom Gowning –Emergency Procedures –Cleanroom Work Habits
3 SSL Cleanroom Training, September 6, 2011 Need for Cleanrooms Failure to control contamination may lead to: –Out of control processes –Electronic components that dont function –Parts that corrode –Optics that dont transmit radiation correctly –Costly rework (with increased risk to hardware) –Loss of time (schedule) –Unreliable performance –Biocontamination of Mars –LOSS OF SCIENCE DATA!
4 SSL Cleanroom Training, September 6, 2011 Definitions: Contamination: any foreign material that has a detrimental effect on a product or process. –Particles (dust, metal flakes, droplets) –Biological contaminates (organisms, viruses, bacteria) –Molecular Residue (Oils, chemicals) –Moisture –Radiation (Ionic and Electromagnetic) Cleanroom: any space constructed and maintained to control forms of contamination. –Typical controls: temperature, humidity, particle filtering, pressurization, protective garments, work habits
5 SSL Cleanroom Training, September 6, 2011 Particle Sizes Visible to the Naked Eye Diameter (microns)
6 SSL Cleanroom Training, September 6, 2011 Certification: Airborne vs. Surface Class (or Classification) – Measure of Airborne particulate contamination by volume per ISO Cleanliness Level – Measure of Surface particle and molecular contamination by area per IEST-STD- CC1246D In the cleanroom, we measure Class regularly. Your Flight Hardware is accepted based upon Cleanliness Level. Air exchange rate, activity levels, gowning requirements, and housekeeping all affect both measures.
8 SSL Cleanroom Training, September 6, 2011 Cleanroom Classifications Laboratory Cleanrooms – Class 10,000 (ISO Class 7) –HEPA filters, increased airflow, positive pressure system. –Smock or Bunny Suit by project. –Cleanroom paper only. No paper, cardboard or wood. Controlled Environments – Class 300,000 (ISO Class 8.5) –May or may not have HEPA filters. –Smocks worn when working on Flight Hardware. –For use with subassemblies and projects that are not contamination sensitive or easily cleaned. –Paper OK. Cardboard and Wood must be encased.
9 SSL Cleanroom Training, September 6, 2011 Cleanroom Design Basics HEPA filters remove >99.999% of airborne particles from supply air. Air is continually supplied to flush room and minimize particle settling Pressurization decreases particle entry through joints, feedthrus, and doorways. Careful material selection minimizes particle shedding, outgassing and corrosion. Housekeeping maintains surface cleanliness and minimizes shedding from walls Gowning areas and cleaning areas permit preparation of personnel and hardware before entry.
11 SSL Cleanroom Training, September 6, 2011 Clean Tents Vertical airflow. HEPA filtered. No positive pressure. No gowning or staging area. Dirty and clean air meet at the curtain. –Turbulent flow draws dirty air into room.
12 SSL Cleanroom Training, September 6, 2011 Hardware and Equipment Entry All hardware, equipment and tooling must be either cleaned and inspected before entering the cleanroom or sealed within bagging material. Double bag all hardware for movement between cleanrooms. Use only approved packaging materials.
13 SSL Cleanroom Training, September 6, 2011 Human Body Contamination Skin flakes Hair Spittle droplets Fingerprint residue Bacteria and viruses Clothing fibers Cosmetic chemicals Dirt, especially from footwear
14 SSL Cleanroom Training, September 6, 2011 Human Body Contamination Huge Quantities! –Millions of particles released each minute –Skin oils, fats, and salts –Lose 50 to 100 hairs per day –5 pounds of dead skin flakes per year –A column of warm air around the body carries these particles upward –Many other emissions and excretions
15 SSL Cleanroom Training, September 6, 2011 Human Body Contamination Bathing with thorough hair washing –Removes contaminants from the body Skin, hair, chemicals Not all removed –Temporary benefits Cutting fingernails –Long and sharp fingernails can rip gloves.
16 SSL Cleanroom Training, September 6, 2011 Street Clothing Wear clothing that is clean and in good condition. Denim is acceptable as long as it is not worn or frayed. No wool, cotton flannel, frayed or badly worn clothing. No shorts, skirts or tank tops in cleanrooms. No sandals or open-toed shoes allowed. (Safety)
17 SSL Cleanroom Training, September 6, 2011 Makeup Cosmetics produce huge quantities of particulate and chemical residue and should not be worn in the cleanroom. Perfume and Cologne are designed to outgas and should not be worn in the cleanroom. Billions of particles can be found on face and gloves of test subjects.
18 SSL Cleanroom Training, September 6, 2011 Food Items, Gum and Candy No drinks, food, candy or gum allowed in cleanroom. –Not in pockets either. Gum and candy stimulate salivation, which increases spitting when talking or sneezing. Face masks are not 100% effective filters.
19 SSL Cleanroom Training, September 6, 2011 Why Cleanroom Garments? The human body generates millions of particles every minute. Fabrics constantly generate, trap and shed millions of particles. Skin, skin oils and body hair are a significant source of contamination. In short, you are a contamination risk!
20 SSL Cleanroom Training, September 6, 2011 Cleanroom Garments A properly work cleanroom garment will reduce particle shedding by 300X. Thousands of particles are still being shed.
21 SSL Cleanroom Training, September 6, 2011 Gowning Procedure 1.Slip on disposable shoe covers. –Use clean side – dirty side protocol. 2.Face mask 3.Bouffant head cover –Cover all your hair. 4.Smock –Cut open bags (dont rip). –Zip or snap all snaps. 5.ESD strap to bare skin 6.Gloves – Nitrile –Do not handle at fingers. –Tape the cuffs to smock to keep the wrist from being exposed.
22 SSL Cleanroom Training, September 6, 2011 Ungowning Procedure 1.Remove tape at wrists. 2.Remove and hang smock. –Do not allow to touch the floor. 3.Remove ESD strap. 4.Remove and trash bouffant head cover and facemask. 5.Step out of cleanroom. –Use clean side – dirty side protocol. 6.Dispose of shoe covers. 7.Dispose of gloves.
23 SSL Cleanroom Training, September 6, 2011 Unplanned Garment Situations Torn or Damaged Glove –Glove over immediately or go to the gowning area and replace. –Do not remove gloves in cleanroom. –Do not continue work. Contaminated Garments –Go to the gowning area and replace immediately.
24 SSL Cleanroom Training, September 6, 2011 Alarms and Emergencies Just leave. –Walk out in your gowns. –Cycle out for cleaning and switch to new before coming back. Call Jeremy McCauley or Steve Marker from a safe location. FIRE ALARM BLACKOUT OXYGEN SENSOR
25 SSL Cleanroom Training, September 6, 2011 Tacky Mats Step on six (6) times whenever you encounter them. To refresh: –Pull slowly starting at numbered corner pull tab. –Work around the edges and gather to middle. –Fold together to capture loose particles. –Dispose in closest trash receptacle toward the outside of the room.
26 SSL Cleanroom Training, September 6, 2011 Work Habits Maintain deliberate actions and behavior. –No unnecessary movement, rubbing, pacing, etc. –Try to stand downwind. Dont touch exposed skin. –Face and glasses, leg, hair, etc. Particle generating practices need special planning and provision. –Soldering, drilling, abrading, wire stripping, etc. –If it can be done outside, do it there. –Ask me for help! Vacuums, protective covers, etc. Work areas must be neat and orderly. Tools should be wiped down and put away. Never reach under your garments. –Go out to the gowning area for cell phones, pens, cameras, etc.
27 SSL Cleanroom Training, September 6, 2011 Work Habits Particles Generated (0.3 micrometers/minute/activity) Motionless, sitting or standing100,000 Head, arm, neck, leg motion300,000 All above with foot motion1,000,000 Standing to sitting or v.v.2,500,000 Walking at 2 mph5,000,000 Walking at 3.5 mph7,500,000 Walking at 5 mph10,000,000
28 SSL Cleanroom Training, September 6, 2011 Work Habits Walk slowly. Minimize movements. Avoid congregating in the cleanroom and near workstations. Lift your feet when walking (dont shuffle). Gloves are required. Do not lean against walls, support hardware, etc. Not all areas of the cleanroom are as clean as others. –Floors, walls, plastic curtains. Work on tables. Cover hardware. Store extras elsewhere.
29 SSL Cleanroom Training, September 6, 2011 Restricted Items Do not bring the following into the cleanroom: –Food, candy, gum, tobacco products –Unapproved pens and markers Ballpoint pens and Sharpies are OK. Cleanroom pens are preferred. –Pencils and erasers –Unsealed wood –Lighters or matches –Cardboard or paper products –Corroded tools –Aerosols of any kind –Any particle-generating material –Any high-outgassing material
30 SSL Cleanroom Training, September 6, 2011 Contamination Control Assembled in Class 100,000 cleanroom (or flowbench). –Subassemblies in 165 are OK. –Final cleaning and closeout of any cavity must occur in cleanroom. Final cleaning and closeout. –Wipe all internal surfaces with IPA. –Inspect to VC-HS+UV From 6 to 18 inches away. Illuminate with >100 foot-candles of white light, remove any visible particulates. Illuminate with >100 foot-candles of black light, remove any visible fibers. Bakeout –Maximum flight temperature for 48 hours. –TQCM data for >2 hours at end of bakeout.
31 SSL Cleanroom Training, September 6, 2011 Planetary Protection Assembled in Class 100,000 or better cleanroom. –Log of exposure to worse environments. Keep it bagged! Enhanced protections: –Face masks –Gloves taped at wrists Biological assay: –each box or boom –a representative PWB just prior to closeout (PFDPU, SWIA, SEP, SWEA electronics, STATIC) –500 spores/m^2 or less Dry Heat Microbial Reduction for harnesses. –125C at <1 torr for 20 hours Hope it will burn up.
32 SSL Cleanroom Training, September 6, Specifics This is a controlled space, not a cleanroom. Wear your smock and gloves. Dont hang your head over the hardware. No final closeout of hardware spaces. Dont be upwind of air currents from building supply or air ionizers. Keep it bagged!
33 SSL Cleanroom Training, September 6, 2011 Who to Contact Jeremy McCauley –CCE and PPE, –Cell: Steve Marker –Facilities and Supplies, Jorg Fischer –Safety and Mission Assurance Manager, Thanks to JPL Cleanroom Certification Course for baseline materials from which this presentation was created.