Paul Burress, MPH, CHP, CIH, CPH Florida State University FCHPS Spring Meeting April 10, 2015

Transcription

1 Paul Burress, MPH, CHP, CIH, CPH Florida State University FCHPS Spring Meeting April 10, 2015

2 FSU Chemistry GA/TA Training Initial 16 Hours (prior to Fall semester): General Laboratory Safety Rules Personal Protective Equipment Chemical Storage, compatibility and transportation Facility Engineering Controls Laboratory Audits RTK- HAZCOM, hazardous waste, spill response Safety Resources, SDS and Hazard Identification Fire Safety/Emergency Response CPR/AED and First aid Case Studies and lessons learned from laboratory accidents Safety shower/eyewash demonstration Chemical Spills exercises Fall Semester Seminar Topics (now CHM 5801): Biosafety concerns in the research laboratory Concepts and terminology in chemical hazard Toxicology Mass Spec, BASS lab and NMR safety Radiation and MAC Lab safety Safety with experimental designs and equipment Introduction to Laboratory Risk Assessment Laboratory Risk Assessment Presentations Laboratory Risk Assessment Presentations Safety considerations with nanomaterials Case studies - Facility Engineering Working with energetic organic compounds Lessons learned from laboratory accidents Online Training (done independently): Cryogen Safety Compressed Gas Safety

3 Common R&D Engineering Controls Ventilation Systems General Single pass room ventilation Direct (or Local Exhaust Ventilation) Fume Hoods (most important for user exposure control) Snorkels, Canopy Hoods, Slot Hoods (adjuncts for heat and nuisance odors) Glove Boxes Fire Suppression Systems, Detection Equipment & Zones Emergency Safety Showers and Eyewashes Chemical Storage Rooms and Permanently Installed Storage Cabinets Waste Piping Electrical Distribution and Grounding

4 Hierarchy of Protective Measures Engineering Controls Warnings & Administrative Controls Personal Protective Equipment (PPE) Elimination of the hazard altogether or Substitution of less hazardous materials should be your first considerations! Of these three remaining measures, Engineering Controls afford the highest level of protection even though they are the least understood and most taken for granted by facility users

5 Who Determines these Controls? Architect & Engineer To some extent, this can be everyone involved in the construction or renovation of the facility! Code Officials Project Project Manager Primary reliance is on this Design Team Customer (future occupants and representatives) Simple engineering controls are sometimes instituted afterwards. These should always be reviewed by Engineering, Code Officials and Safety staff for appropriateness and consistency Ensure minimum requirements are met Provides Overall Coordination Communicate needs and wishes Construction Manager Contractors Construct what is specified, feasible and code compliant

6 Communication Miscues can Occur

7 General Ventilation Design Criteria A fume hood should be available for every 2 lab personnel (NFPA 45 guidance) 25 ft3/ft2 of horizontal fume hood work surface, minimum flow volume is required (NFPA 45 guidance) 4 ACH is the minimum in any laboratory with chemicals present (NFPA 45 guidance) 4 12 ACH lab ventilation rate range, 8-12 is typical for occupied settings (OSHA guidance) Potentially hazardous exhaust cannot be recirculated (NFPA 45 rule - Florida) IBC/FBC - minimum cfm/ft2 criteria Keep in mind that studies consistently show fume hoods are actually only in-use <5% of the time and ventilation rates for unoccupied demands should be much less than during use.

8 Sustainability (Energy/Environmental) Drivers (Labs21, I 2 SL, UC Berkeley, DOE) Leadership in Energy and Environmental Design (LEED certification) U.S. Green Building Council Comparison to Offices (IAQ and cost differences) Sustainable product availability & marketing Ductless Fume Hoods Automatic Fume Hood sash closers High-Efficiency (Low Flow) Fume Hoods VFD fans Building Automation Systems (occupancy sensors and unoccupied setbacks) Atmospheric sampling systems Energy recovery systems passive and active

9 Training Issues But Users rarely receive facility system operations training! Laboratory personnel need to understand the capabilities and limitations of the ventilation systems, and other exhaust devices associated with such equipment and how to use them properly (National Academies Prudent Practices in the Laboratory)

10 Research Building Air Flow Diagram

11 AHU Sections There are four basic parts in most of our industrial AHUs: Particulate Filters Heating Coils Cooling Coils Supply Fans (or Fan Walls)

12 Supply & Return Ducting These ducts are usually rectangular in shape and constructed of galvanized metal (dimensions matter) External insulation is often applied to prevent condensation and control energy loss Flexible ducting is often used near terminals

13 Hazardous Exhaust Ducting As opposed to supply ducting, is usually round and uninsulated May be constructed of galvanized, spiral wound or welded stainless steel. Welded stainless steel affords the highest degree of protection but also costs the most All joints must be welded or sealed

14 Good Laboratory Exhausts Are designed to discharge contaminants above and away from building with as few potential obstructions as possible Properties of best designs: have a minimum 10 effective stack height above the roofline are located outside of the building envelope are located to prevent contaminant reentry into the served or neighboring building air intakes have impellers impervious to corrosives and are constructed of non-sparking materials use unconditioned air to maintain > 3000 fpm discharge velocity drain rain have redundancy are not overtaxed

15 Poor Laboratory Exhausts Direct contaminants down Do not drain rain Do not have high enough effective stack heights

16 Laboratory Ventilation Approaching maximum practical fume hood density 3000 fpm exhaust Simplified Laboratory Air Exchange Scheme Outside Air Parameters 25 x 40 area with 10 ceilings = 10,000 ft3 lab volume 10 ACH = 100,000 cfh total exhaust or 1,667 cfm 6 wide fume hood with 18 working height = 7.5 sq ft 100 fpm face velocity = 750 cfm hood exhaust required NFPA suggests 25 cfm/ft2 minimum flow (~250 cfm) Fume Hood Open: 750 cfm Shut: 250 cfm General Exhaust Hoods open: 0 cfm Hoods shut (occupied): 667 cfm Hoods shut (unoccupied): 0 cfm Supply Air Hoods open: 2,850 cfm Hoods shut (occupied): 1,517 cfm Hoods shut (unoccupied): 850 cfm Fume Hood Open: 750 cfm Shut: 250 cfm Door 150 cfm Offset Outside Air AHU Return Air (from non-laboratory spaces) Fume Hood Open: 750 cfm Shut: 250 cfm Fume Hood Open: 750 cfm Shut: 250 cfm Supply Air (to non-laboratory spaces)

17 Hazardous Exhaust Ventilation General These are the registers/grills/vents, usually located in ceilings or walls, which exhaust the mixed air from the general space that personnel occupy Local/Direct The aim of this equipment is to carry any generated contaminants directly out of the area before people can breathe it. These type devices are covered in more detail in a separate module The components chosen and their placement have major influences on function It is essential to maintain adequate flow directions, volumes and pressurization schemes Automation equipment and controls require routine inspection (setbacks, occupancy sensors, air monitoring, sash position sensors, sash closers ) LEV equipment (fume hoods & downdraft tables are ideal for exposure control) Snorkels, canopy hoods, slot hoods - are adjuncts mainly for heat and nuisance dust or odor control Gloveboxes when used for employee protection, need to be routinely inspected and maintained CFM/ft2 or ACH has been used extensively These parameters alone are not ideal for protection. Several other conditions must be taken into account (ventilation system layout, Laboratory layout and obstructions, ceiling heights, even contaminant properties) The big push industry-wide is for Fluid Dynamic Modeling (CFD), is it done?

18 Concentration (ppm) Laboratory Clearance Times via General Ventilation (assuming ideal mixing in a single pass system & $6/CFM/yr) 10,000 ft3 Laboratory (clearance to 10% original concentration) Air Changes/Hour (ACH) Time (min) Cost/year (approx.) $1, $4, $8, $10, $12, $20,000 1 ACH 4 ACH 8 ACH 10 ACH 12 ACH 20 ACH Time (minutes)

19 Concentration (ppm) Fume Hood Clearance Times (assuming ideal mixing) This is why Fume Hoods are valuable! Clearance times are significantly quicker than in open labs, ideal ACH rates approach 1800 Sash glass affords significant physical protection Contaminants generated in a fume hood are not circulated through the laboratory, and are not breathed by occupants, prior to being exhausted Time (seconds)

20 Fume Hoods Hood Types Conventional (Constant Volume) Restricted Bypass High Efficiency (lower flow demands) Auxiliary Ductless (particulate and other filter media) Hood Configurations Benchtop Distillation Demonstration (California Hood) Floor (Mis-labeled Walk-In ) Common Systems CV CV2 VAV

21 Constant Volume (CV) Conventional Fume Hoods This type of hood can experience potentially turbulent flow and/or containment problems when sash positions other than the approved working height are used, unless they are integrated into an HVAC controls system that adjusts exhaust flow based on the hood sash position

22 After improper installation

23 Bypass Fume Hoods These have been designed to minimize face velocity changes due to sash repositioning. This is especially important for the extreme increases that would be experienced as the sash approaches fully closed. The design goal is typically to limit increases to <3.5 times that at the working sash height (<350 fpm maximum)

24 Face Velocity Differences (CV vs. Bypass Type Fume Hoods in a CV system) FACE VELOCITY (FPM) Bypass Hood Turbulence becomes increasingly problematic as face velocity exceeds ~125 fpm Conventional Hood SASH HEIGHT (INCHES)

25 Auxiliary Air Fume Hoods NFPA requires introduction of auxiliary air to be exterior to the hood sash, older models (such as shown here) introduced this air just inside the sash. These hoods have proven to have serious performance problems. The National Research Council recommends that these hoods not be purchased and that existing ones be replaced or disabled ASAP Existing installations must have the auxiliary supply disabled. Supply ducts should be permanently disconnected and/or capped to keep them from being inadvertently returned to service and to prevent outside air entrainment via static pressure differences between outdoors and the laboratory

26 Low-Flow High Efficiency Fume Hoods Designed to provide adequate or better containment performance at lfpm face velocity than a conventional 100 lfpm hood We have several of these installed on campus but all of these are currently operating at 100 lfpm and the promised performance has not been reliably realized in our laboratories The increased initial cost and complexity have made these an unsafe gamble

27 ASHRAE-110 Testing This is a quantitative testing standard, published in 1995, that uses a neutrally buoyant tracer gas (i.e. SF6) and smoke to assess fume hood performance characteristics under a prescribed set of static and dynamic operating conditions This test must be done at the end of any new installation or renovation projects to prove performance goals were achieved before the hoods are used, while the project team is still available and warranties may still be in effect The testing needs to be scheduled following any operations that may impact hood performance such as HVAC Test and Balancing or component replacement/reconfiguration Quantitative data obtained during this testing serves as a baseline for future face velocity verifications, observed deviations from the baseline values warrants system inspection and repair and/or repeated ASHRAE-110 evaluation

28 ASHRAE-110 (1995)

29 High Efficiency Hood Data [SF6 ave] (Reformatted Data)

30 Snorkels & Canopy Hoods These are used to remove nuisance heat, dust or odors directly at the source, before it mixes with general laboratory air

31 Quality & Performance Commissioning Test & Balance ASHRAE-110 (1995) SEFA 1 (2006) A comprehensive and independent verification that building systems or structures were installed and are performing as specified by the designers. This commonly includes the HVAC mechanical, electrical, control and plumbing systems Consists of third-party verification that the ventilation system airflow and components were installed as specified and are working within prescribed bands Must be performed before other validations such as commissioning or fume hood ASHRAE-110 testing is performed Is performed after all work that may effect system performance has been completed Quantitative and Qualitative Testing of fume hood containment performance under several static and dynamic configurations using a neutrally buoyant tracer Recommended Practices for Laboratory Fume Hoods Standard Reference for Hoods, other LEV equipment and lab ventilation 2006 version updated face velocity range acceptance criteria Trade association document that influences and is influenced by professional organization consensus standards (ANSI, ASHRAE, ACGIH, NFPA) and OSHA

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33 Don t have blind faith that systems are properly designed or functioning

34 Duct Materials Fume hoods require exhaust ducting that is compatible with products intended to be used. Since future use in research laboratories is hard to predict, welded stainless steel is preferred for almost all installations.

35 Duct Materials Ducts using highly corrosive chemicals, must be inspected periodically, especially in close proximity to points of use Some operations such as heating perchloric acid, require special decontamination and clearance before any maintenance can be performed

36 Ventilation Component Maintenance Corrosion anywhere on laboratory ventilation systems should be cause for serious concern and must be promptly reported to facility managers

37 Ventilation Component Maintenance This is a close-up of one the exhaust fans in the previous slide The Architect specified weather resistant construction in the original plans but this was obviously not installed or caught during subsequent inspections Routine maintenance should identify this type of deficiency

38 Ventilation Component Maintenance Correct sound/vibration insulation materials must be used and maintained, especially when exposed to harsh weather conditions This is often the most vulnerable component in exhaust ducting systems

39 Recognizing Failures Requires Knowledge of the Overall System Operation External signs may not always be evident, particularly when internal components are less robust than exterior materials This occurred in a cleanroom where concentrated acids were frequently used in a fume hood. The hood served by this exhaust fan exhibited proper face velocity, normally indicative of proper operation. In this case though, it was due to positive room pressurization (excess supply ventilation) pushing air through the hood. This was a difficult problem to diagnose until a thorough system inspection was performed by maintenance staff!

40 Aerial Clues Workers on the roof may have noticed something was wrong

41 Wrong Type Hood The Labconco hoods in the VWR Ready Ship program are blocked bypass hoods The sales reps, furniture reps and installers did not think about the system when replacing the old fume hood and it was installed without proper modifications ASHRAE testing would very likely have uncovered this problem

42 Incomplete Installation The corrosive containing base cabinets were partially disassembled in this area for this installation The importance of the vent holes and countertop cuts was not given enough attention Project Management, Building Code, EH&S or any oversight may have caught this earlier Fortunately, the fix is cheap and easy to affect and ASHRAE testing was eventually done

43 Sash Glass Affords Significant Protection Sash glass is laminated and has proven to be quite effective at stopping spills into the laboratory and containing projectiles

44 Blast Shield Damage This is a portable heavily bottom weighted ½ thick piece of Lexan used to protect users from potentially energetic reactions This was located to the left of the reaction

45 Sash Glass Standard laminated safety glass that was between the user s face and the reaction Note the spider web type damage This glass was actually closer than the blast shield located to the left

46 Recognizing Failures Sometimes it doesn t require any special knowledge to notice abnormalities but usually the signs/symptoms are more subtle Again always trust your instincts and report anything that does not seem right

47 Improper Use Can Easily Negate Protection Past laboratory inspections revealed many user created conditions that rendered fume hoods inoperable Spending $5,000 per year to have a ventilated storage area was never a design goal but ignorance and lack of accountability allowed these types of used to become commonplace This issue has almost ceased to exist in recent years due to increased awareness and consistent enforcement

48 User Modifications When users become use to having to fend for themselves, they can become quite adept and creative

49 User Modifications Will probably be functional but my be highly inappropriate