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Lab Topics

Lab Manager’s Guide to Construction and Maintenance

If you’re a lab manager your area of expertise is probably not construction. However, it is common for lab managers to inherit the responsibility of planning, budgeting and supervising any construction or maintenance project related to their labs. If you ever find yourself in this position, this guide is for you.

The following are the four steps of a typical construction or maintenance project.


Step 1:  Determining the need

This is the easiest part of any project. You’re probably being reminded of it constantly. It might be that the fume hoods are old and not working properly or there’s not enough room in the lab to accommodate the equipment or personnel, there’s not enough electric or gasses for new equipment, the HVAC system doesn’t work properly, etc. Identify the conditions you want remedied.


Step 2:  Preparing a scope of work, budget and schedule

Most lab managers have to submit their request for work to either a purchasing or engineering department. Even if you don’t have to do this you’l still want a written description of what is to be done (the scope of work) the amount it’s going to cost and how long it’s going to take. This is where you call Laboratory Design & Construction. We’ll meet with you, assess the problem, develop a scope of work, and create a cost proposal and a schedule for your project. There is no cost for an initial meeting and most proposals are developed free of charge. (There may be a cost on larger projects.)


Step 3:  Design

The design phase is only required on larger construction or renovation projects. It’s mandatory when the project will require a construction permit. The appropriate governing authority will need to see a floor plan drawing of what is to take place as well as some construction details describing various parts of the project. LD&C can handle all your design requirements for you.


Step 4: Construction

This is the most visible part of the project. This is where the existing lab gets renovated or the new lab gets built. LD&C can provide all the personnel, materials and supervision required to complete your project.


If you have any questions feel free to give me, Bruce Ciloski, a call. You can reach me at 832.256.0014 or email me at bruce@laboratorydesign.com.

Introduction to Laboratory Chemical Storage II

  1. Introduction
    In the previous article, “Introduction to Laboratory Chemical Storage part 1” we took a look at the basics of a Chemical Hygiene Plan. This brochure will list chemical storage tips that will serve as reminders for your lab personnel or a quick guide to find possible chemical storage problems within your lab.
  2. Relevant Codes Recap
    The applicable code regarding chemical storage is the U.S. Department of Safety & Health Administration Standards -29 CFR 1910.1450 Subpart Z. This standard is most commonly referred to as “The Laboratory Standard.” The following information in this article will highlight many of the items in the standard but if you want the complete text you can consult the Code of Federal Regulations. The information concerning laboratory chemical storage is found in Part 1910 of Title 29 (cited as 29 CFR 1910) section 1450 of subpart Z, “Occupational Exposures to Hazardous Chemicals in Laboratories.”
  3. A Storage Methodology: Categorical Storage
    How you organize your storage space is vital to the overall effectiveness of your chemical storage plan. One method of storage that has wide acceptance is categorical storage. This is the storage of chemicals based on their inclusion in one of ten categories. The ten most commonly cited segregation classifications are: flammables, oxidants, reducers, concentrated acids, concentrated bases, water reactive, extreme toxics, peroxide formers, pyrophorics and gas cylinders.

    • The first five groups are separated to avoid accidental contact with an incompatible material which could result in a violent or explosive reaction.
    • Water reactive is isolated to lessen the probability of their involvement in a fire situation.
    • Extreme toxics are segregated to provide some degree of control over their distribution and to lessen the possibility of accidental spills.
    • Peroxide formers should be stored in a cool, dark environment, whereas pyrophorics need only contact with air to burst into flames.
    • Gas cylinders have the added hazard, regardless of their contents, of possessing high kinetic energy due to the compressed nature of the gas.

    There is not clear consensus on what and how many classes of chemicals should be segregated. To a large extent, how the chemical groups are divided and assigned will depend largely upon the amount of space available.

  4. Chemical Storage tips
    1. There are four major modes of entry into the human body for chemicals: 1. Inhalation. 2. Skin Absorption. 3. Injection. 4. Ingestion. Inhalation and skin absorption are the predominate occupational exposure you may expect to encounter in the laboratory.
    2. A place for everything and everything in its place. Every chemical in the laboratory should have a definite storage place and should be returned to that location after each use.
    3. Typically, solvents, acids, bases, reactives, oxidizers, and toxins will be stored separately. Separation refers to physical separation of containers and isolation of potential spills and releases. Separate cabinets or isolated areas within a central storage area should be utilized for segregated storage of incompatibles.
    4. Hazardous chemicals should never be stored on the floor. Containers should be kept on low shelves or in cabinets. The shelves should have a lip on the forward edge to prevent bottles from slipping off.
    5. Utilize a compatible/suitable container for experiments, stored, chemicals and collected wastes. In instances of corrosive wastes or solvents, the use of metal containers is often unsuitable, even if the solvents were originally shipped in metal containers. In these instances, plastic carboys or lined metal containers may be more suitable.
    6. Be on the lookout for any sign of chemical leakage. Containers storing chemical waste must be inspected weekly for any sign of chemical leakage. Containers of all types should be free of rest and dents.
    7. Caps and covers for containers shall be securely in place whenever the container is not in immediate use.
    8. NFPA labeling shall appear on cabinets and room doors at approximately waste level or lower to allow adequate visualization in dense smoke conditions.
    9. All containers used for storage (even short term) shall be labeled in accordance with hazard communication regulations and NFPA fire codes. At a minimum, all containers must be labeled with regard to content and general hazard.
    10. Metal drums used for storage and dispensing of flammable chemicals shall be properly grounded. Ground cables shall be available and utilized in any lab using metal storage containers for flammable liquid storage.
    11. Bulk quantities of chemicals (i.e. larger than one gallon) must be stored in a separate storage area. Transfer of flammable liquid from five gallon or larger metal containers may not be done in the laboratory.
    12. Liquid or corrosive chemicals should never be stored on shelves above eye level.
    13. Glass containers should not touch each other on shelves.
    14. Fume hoods should not be used as general storage areas for chemicals.
    15. Gas cylinders must be securely strapped to a permanent structure.

If you have any questions feel free to give me, Bruce Ciloski, a call. You can reach me at 832.256.0014 or email me at bruce@laboratorydesign.com.

Introduction to Laboratory Chemical Storage I

  • Introduction
    Even if you use only a small amount of chemicals in your laboratory it’s important that you store them properly. Not only is it common sense for your safety and for the safety of those working in your lab, but many labs are required to meet federal guidelines for their chemical storage. Failing to meet these guidelines could have serious repercussions for your organization regarding certifications, inspections, or legal liability if a chemical related injury should occur.
  • Relevant Codes
    The applicable code regarding chemical storage is the U.S. Office of Safety & Health Administration (OSHA) Standards -29 CFR 1910.1450 Subpart Z. This standard is most commonly referred to as “The Laboratory Standard.” The following information in this article will highlight many of the items in the standard but if you want the complete text you can consult the Code of Federal Regulations. The information concerning laboratory chemical storage is found in Part 1910 of Title 29 (cited as 29CFR 1910) section 1450 of subpart Z, “Occupational Exposure to Hazardous Chemicals in Laboratories.”

Who does the code apply to?
The OSHA Lab Standard does not apply to all laboratories, but where it does apply, it must be implemented. If your laboratory meets any of the following four criteria you are subject to the laboratory standard.

  1. Chemical manipulations are carried out on a laboratory scale. That is, the work with chemicals is in containers of a size that could easily and safely be manipulated by one person.
  2. Multiple chemical procedures or chemicals are used.
  3. Protective laboratory practices and equipment are available and in common use to minimize the potential for employee exposure to hazardous chemicals.
  4. The procedures involved are not part of a production process whose function is t produce commercial quantities of materials, not do the procedures in any way simulate a production process.

The fourth criterion would normally exclude quality control laboratories in industrial operations because they “are usually adjuncts of production operations that typically perform repetitive procedures for the purpose of monitoring a product or process.”

This criterion also would normally exclude pilot plant operations, which are typically closely connected with production processes. However, if pilot plant operations are an integral part of a research function for the purpose of evaluating a particular effect (for example “the operations do not proceed to production but remain part of the research activity”) then that pilot plant operation may be subject to the standard.

The Chemical Hygiene Plan
If your lab is subject to the standard, the first requirement is for your organization to develop a chemical hygiene plan. This plan is more than just a procedure for chemical storage. In fact, chemical storage is just one part of the plan. The Chemical Hygiene Plan is actually a safety manual based on OSHA requirements for laboratories. Fortunately, the safety manual/plan you’re currently using probably already incorporates most of what OSHA requires. You can compare the items listed below with your existing procedures to see they match. If they do then you’re well on your way to creating your required Chemical Hygiene Plan. If not, incorporating the items listed below will bring you closer to compliance.

It’s a good idea to put the plan into manual form. This way you can easily refer to it as well as use it for instructing new personnel. It also makes it easier to copy and distribute to other people in the lab.

Since The Chemical Hygiene Plan is the first step in proper chemical storage, the remainder of this article will highlight the basic items that should be included. More specific chemical storage information is covered in Introduction to Laboratory Chemical Storage Part 2.

Components of the Chemical Hygiene Plan

    1. Basic Rules and Procedures (See 29CFR 1910.1450 for full listing.)
      1. Avoidance of “routine” exposure: Develop and encourage safe habits; avoid unnecessary exposure to chemicals by any route.
      2. Do not smell or taste chemicals. Vent apparatus which may discharge toxic chemicals into local exhaust devices.
      3. Eating, smoking, etc.: Avoid eating, drinking, smoking, gum chewing, or application of cosmetics in areas where laboratory chemicals are present; wash hands before conducting these activities.
      4. Use of hood: use the hood for operations which might result in release of toxic chemical vapors or dust.
      5. Confirm adequate hood performance before use; keep hood closed at all items except when adjustments within the hood are being made; keep materials store din hoods to a minimum and do not allow them to block vents or air flow.
      6. Leave the hood “on” when it is not in active use if toxic substances are stored in it or if it is uncertain whether adequate general laboratory ventilation will be maintained when it is “off”.
      7. Always use a hood previously evaluated to confirm adequate performance with a face velocity of at least 100 linear feet per minute.
    2. Chemical Procurement, Distribution, and Storage
      1. Procurement. Before a substance is received, information on proper handling, storage, and disposal should be known to those who will be involved. No container should be accepted without an adequate identifying label. Preferably, all substances should be received in a central location.
      2. Stockroom/storerooms. Toxic substances should be segregated in a well identified area under local exhaust ventilation. Chemicals which are highly toxic or other chemicals whose containers have been opened should be in unbreakable secondary containers. Stored chemicals should be examined periodically (at least annually) for replacement, deterioration, and container integrity. Stockroom/storerooms should not be used as preparation or repackaging areas. They should only be open during normal working hours and should be controlled by one person.
      3. Distribution. When chemicals are hand carried, the container should be placed in an outside container or bucket. Freight only elevators should be used if possible.
      4. Laboratory storage. Amounts permitted should be as small as practical. Storage on bench tops and in hoods is inadvisable. Exposure to heat or direct sunlight should be avoided. Periodic inventories should be conducted, with needed items being discarded or returned to the storeroom/stockroom.
    3. Environmental Monitoring
      Regular instrumental monitoring of airborne concentrations is not usually justified or practical in laboratories but may be appropriate when testing or redesigning hoods or other ventilation devices or when a highly toxic substance is stored or used regularly.
    4. Housekeeping, Maintenance, and Inspections
      1. Cleaning. Floors should be cleaned regularly.
      2. Inspections. Formal housekeeping and chemical hygiene inspections should be held at least quarterly for units which have frequent personnel changes and semiannually for others; informal inspections should be continual.
      3. Maintenance. Each wash fountain should be inspected at intervals of not less than 3 months. Respirators for routing use should be inspected periodically by the laboratory supervisor. Other safety equipment should be inspected regularly (Every 3-6 months.)
      4. Passageways. Stairways and hallways should not be used as storage areas. Access to exits, emergency equipment, and utility controls should never be blocked.
    5. Medical Program
      1. Compliance with regulations. Regular medical surveillance should be established to the extent required by regulations.
      2. Routine surveillance. Anyone whose work involves regular and frequent handling of toxicologically significant quantities of a chemical should consult a qualified physician to determine on an individual basis whether a regular schedule or medical surveillance is desirable.
      3. First aid. Personnel trained in first aid should be available during working hours and an emergency room with medical personnel should be nearby.
    6. Protective Apparel and Equipment
      These should be included in each laboratory:

      1. Protective apparel compatible with the required degree of protection for substances being handled.
      2. An easily accessible drench-type safety shower.
      3. An eyewash fountain.
      4. A fire extinguisher.
      5. Respiratory protection, fire alarm and telephone for emergency use should be available nearby; and other items designated by the laboratory supervisor.
    7. Records
      1. Accident records should be written and retained.
      2. Chemical hygiene plan records should document that the facilities and precautions were compatible with current knowledge and regulations.
      3. Medical records should be retained by the institution in accordance with the requirements of state and federal regulations.
    8. Signs and Labels
      Prominent signs and labels of the following types should be posted.

      1. Emergency telephone number of emergency personnel/facilities, supervisors, and laboratory workers.
      2. Identify labels, showing contents of containers (including waste receptacles) and associated hazards.
      3. Location signs for safety showers, eyewash stations, other safety and first aid equipment, exits, areas where food and beverage consumption and storage are permitted.
      4. Warnings at areas or equipment where special or unusual hazards exist.
    9. Spills and Accidents
      1. A written emergency plan should be established and communicated to all personnel; it should include procedures for ventilation failure, evacuation, medical care, reporting and drills.
      2. There should be an alarm system to alert people in all parts of the facility including isolation areas such as cold rooms.
      3. A spill control policy should be developed and should include consideration of prevention, containment, cleanup and reporting.
      4. All accidents or near accidents should be carefully analyzed with the results distributed to all who might benefit.
    10. Information and Training Program
      1. Aim: to assure that all individual at risk are adequately informed about the work in the laboratory, its risks, and what to do if an accident occurs.
      2. Emergency and Personal Protection Training; every laboratory worker should know the location and proper use of available protective apparel and equipment.
    11. Waste Disposal Program
      1. Aim: To assure that minimal harm to people, other organisms, and the environment will result from the disposal of waste laboratory chemicals.
      2. Content: The waste disposal program should specify how waste is to be collected, segregated, stored, and transported and include considerations of what materials can be incinerated. Transport from the institution must be in accordance with DOT regulations.
      3. Discarding chemical stocks: Unlabeled containers of chemicals and solutions should undergo prompt disposal; if partially used, they should not be opened.
      4. Frequency of Disposal: Waste should be removed from the laboratories to a central waste area at least once per week and from the central waste storage area at regular intervals.
      5. Method of disposal: Incineration in an environmentally acceptable manner is the most practical disposal method of combustible laboratory waste. Indiscriminate disposal by pouring waste chemicals down the drain or adding them to mixed refuse for landfill burial is unacceptable. Disposal by recycling or chemical decontamination should be used when possible.

Many laboratories are required to meet OSHA standards for chemical storage. For those labs that must be compliant, the first step is to develop a chemical hygiene plan. Your lab’s chemical hygiene plan should address the following:

      1. Basic rules and procedures.
      2. Chemical procurement, distribution and storage.
      3. Environmental Monitoring.
      4. Housekeeping, Maintenance and Inspections.
      5. Medical Program.
      6. Protective Apparel and Equipment.
      7. Records.
      8. Signs and Labels.
      9. Spills and Accidents.
      10. Information and Training Program.
      11. Waste Disposal Program.

If you have any questions feel free to give me, Bruce Ciloski, a call. You can reach me at 832.256.0014 or email me at bruce@laboratorydesign.com.

Air Conditioning Systems For The Laboratory

One of the costliest items in a laboratory construction project is the air conditioning system. Labs need more air than almost any other type of facility and supplying that air can be expensive. The decisions you make, or let others make for you, in the design phase of the project are going to have a major impact on your construction budget and on the eventual operating costs of your facility.

A quick review of the two major types of air conditioning systems used in the laboratory will help save you money and ensure that your lab meets both your operational and fiscal requirements.

Two Major Types of Systems
Air conditioning systems for laboratories can be classified into two categories: Constant Volume (CV) and Variable Air Volume (VAV).

Constant Volume System
A constant volume air system is one that exhausts a constant amount (volume) of air through the lab fume hoods while at the same time supplying a constant volume of air into the laboratory.

In a constant volume system the amount of air exhausted and supplied is constant regardless of fume hood usage or sash position. The same amount of air is supplied to the room because the same amount is always being exhausted.

Advantages of a Constant Volume System

  • Since a basic assumption of the design is that all hoods will be in operation at all times and that they will be exhausting at a constant rate, it is likely that the equipment specified for a CV system is of sufficient size to provide enough air for a safe, comfortable lab.
  • If the supply equipment of the AC system has been designed to accommodate expansion (increase in the number of hoods, room size, etc.) the addition of the new hoods is easily accomplished without an uncomfortable lack of supply air or the need for additional supply equipment.
  • The constant volume system is simple. It is simple to design, install and maintain since the equipment is conventional industrial air conditioning equipment. The start-up and testing, installation, and maintenance can be performed by conventional experienced HVAC (Heating, Ventilation, Air Conditioning) contractors. Constant Volume air systems are tried and true; they are the antithesis of cutting edge technology.
  • The initial cost of a CV system is typically lower than a VAV system. Since VAV requires more controls and more sophisticated equipment they tend to be more expensive.

Disadvantages of a Constant Volume System

  • The disadvantage is energy costs. CV systems exhaust a lot of conditioned air. Conditioned air equals energy costs. Depending on the size of your lab, the number of hoods, and the way in which your lab’s air conditioning costs are accounted for, this cost can be considerable.
  • There have been some attempst to modify the CV system in order to reduce energy costs. The most notable attempt being the auxiliary air system. This system brings in unconditioned air form outside the building and supplies it directly in front of the fume hood sash opening. The hood then exhausts this unconditioned air and only a portion of the lab’s conditioned air. Unfortunately, due to the temperature of the undconditioned air (hot in the summer, cold in the winter) auxiliary air systems can make for an uncomfortable lab.
  • Since auxiliary air hoods and additional supply fans also add to the cost and maintenance of the lab, these systems are decreasingly popular.

Variable Air Volume Systems
Variable Air Volume (VAV) systems vary the amount of air being exhausted and supplied to a lab based upon the usage of the fume hoods.

If the hood sash is open and more air is required to pass through the hood the VAV system increases the exhaust flow from that hood and at the same time increases the amount of air supplied into the lab.

If the hood sash is closed the VAV system decreases the exhaust flow and reduces the amount of air supplied to the lab.

According to the manufactures of VAV equipment, this increase and decrease of the air exhausted is accomplished while maintaining a constant 100 fpm across the face of the hood.

VAV systems differ in how they measure the amount of air to be exhausted. Some systems utilize a sensing device built into the side wall of the hood to measure the air volume drawn into the hood. As the volume increases the sensor activates and increases the exhaust. A decrease in the air volume results in a reduction of the exhaust.

Other systems use a sash position sensor. This sensor tracks the location of the hood sash and increases or reduces the exhaust depending on the sash location.

Besides a sensing and control mechanism, most VAV systems require a special VAV style hood. This type of hood only allows air to flow into the hood from the sash opening. This is different from a more common hood style known as a bypass hood. A bypass hood allows air into the hood through a grille when the sash is closed. This additional air allowed into the hood is undesirable when using a VAV system.

Other items of equipment that may be used in conjunction with a VAV system include an automatic sash positioning unit and a sash alarm. The sash positioning unit sensor opens a fume hood sash whenever a person is detected to be in front of the hood and closes the sash when the person walks away. The sash alarm emits an audible or visual alarm or both whenever a sash has been open for a selected length of time. This alarm reminds users to close the sash.

A key element to the success of a VAV system is found not in the equipment but in the design criteria used to develop the system. The crucial idea in this development being “diversity”. Diversity, as it applies to laboratory ventilation, is the assumption that only a certain percentage (typically less than 50%) of all hoods in a lab will be operating at their maximum capacity at any one time. In other words, not all hoods will have their sashes fully open at all times thereby exhausting the maximum amount of air possible at all times.

If not all the hoods are exhausting their maximum amounts of air at one time then the air conditioning equipment supplying the lab need not be sized to accommodate this demand. The equipment can be sized to handle a smaller volume of air supplied and exhausted. This downsized equipment is typically less expensive and thereby results in a cost savings.

When utilizing diversity in design it is important to be cautious. The reason for this is that since the system is sized to account for a percentage of the hoods to be in full operating capacity at one time, if this percentage is exceed the supply to the lab may be insufficient.

Advantage of a Variable Air Volume System

  • The primary advantage of a VAV system is the cost savings resulting from reduced energy consumption. Since the system exhausts less conditioned air it requires less conditioned air with resulting lower energy costs.
  • Another advantage is the reduction in size of the HVAC equipment. Since less air is required the equipment can be down sized. This is a distinct advantage if space is at a premium. A subsequent reduction in equipment cost is also achieved.

Disadvantages of a Variable Air Volume System

  • The initial equipment cost for a VAV system is typically higher than a CV system. This is due to the cost of design, equipment and installation required of a VAV system. Many systems can achieve a payback due to reduced energy costs. However, if the initial project budget is tight this payback may be insufficient incentive to make the initial capital outlay.
  • VAV systems are also more complex with dampers and additional controls. In duct dampers can deteriorate with negative effects on the overall system. Additional controls also add increased maintenance concerns.
  • VAV systems are also very dependent on accurate diversity calculations. If the diversity percentages built into the system are “wishful thinking” and not accurate reflections of how the lab hoods are utilized the entire lab air system may be inadequate.

If you have any questions feel free to give me, Bruce Ciloski, a call. You can reach me at 832.256.0014 or email me at bruce@laboratorydesign.com.

A Guide to Fume Hood Codes and Standards

Sometimes it seems that almost everything in a laboratory is governed by an alphabet soup of government agencies and regulations. We are all familiar with the acronyms OSHA, EPA, NIOSH, and FDA and how they impact our labs. It’s the same with fume hoods. Their installation, operation and maintenance are guided by a variety of governmental and industry organizations. Fortunately, understanding who and what determines proper fume hood operation is not as difficult as it might first seem.

Codes, Standards and Recommended Practices
The following are the primary organizations and standards regarding fume hoods:

OSHA Part 1910.1450. OSHA stands for Occupational Safety and Health Administration. The agency regulations regarding fume hood operation are listed in the Code of Federal Regulations Volume 29 Part 1910.1450. This code addresses several aspects of laboratory design and operation. Regarding hoods it is primarily concerned with airflow at the face of the hood, monitoring, maintenance and exhaust.

ANSI/ASHRAE 110-1995. Method of Testing Performance of Laboratory Fume Hoods. This standard is published by the American National Standards Institute and the American Society of heating, Refrigerating and Air Conditioning Engineers, Inc. It concerns itself primarily with methods of testing fume hoods to check their operation.

ANSI/AIHA Z9.5. Titled “The American National Standard for Laboratory Ventilation” this standard is published by ANSI and the American Industrial Hygiene Association. It covers a variety of lab ventilation issues including hood monitoring, face velocities and exhaust.

NFPA 45. This standard is prepared by the National Fire Protection Association. It recommends hood construction, location, fire protection, specialty hoods, identification, inspection, testing and maintenance and exhaust.

SEFA 1.2-1996. SEFA is the Scientific Equipment & Furniture Association. Its publication “Laboratory Fume Hoods Recommended Practices” covers design requirements of hoods, face velocities and testing.

Special Concerns
Items of immediate interest to lab personnel that are addressed in the codes and standards include:

  1. Air flow
  2. Monitoring/Alarms.
  3. Maintenance/Inspection.
  4. Exhaust.

1. Air Flow

Proper air flow at the face of the hood is probably the most common cause of confusion regarding fume hood operation. Here are what the codes and standards say:

OSHA: “General air flow should not be turbulent and should be relatively uniform throughout the laboratory, with no high velocity or static areas; air flow into and within the hood should not be excessively turbulent; hood face velocity should be adequate. (Typically 60-110 fpm.)”

ANSI/AIHA Z9.5: “Each hood shall maintain an average face velocity of 80-120 fpm with no face velocity measurement more than plus or minus 20% of average.”

SEFA: “Face velocities of laboratory fume hoods may be established on the basis of the toxicity or hazard of the materials used or the operations conducted within the fume hood. Note: Governmental codes rules and regulation may require specific face velocities. A fume hood face velocity of 100 fpm is considered acceptable in standard practice. In certain situations face velocity of up to 125 fpm or as low as 75 fpm may be acceptable to meet required capture velocities of the fume hood.”

2. Monitoring/Alarms

Many older labs are equipped with fume hoods that do not have air flow monitoring devices. The type of device is not specified, but according t the following codes and standards if you’re putting in a hood or remodeling an older one they are now a requirement.

OSHA: “….each hood should have a continuous monitoring device to allow convenient confirmation of adequate hood performance before use. If this is not possible, work with substances of unknown toxicity should be avoided or other types of local ventilation devices should be provided.”

ANSI/AIHA Z9.5: “New and remodeled hoods shall be equipped with a flow-measuring device.”

NFPA 45: “New and remodeled hoods shall be equipped with a flow-measuring device.

3. Maintenance/Inspection

As with all equipment maintenance is important to proper operation.

OSHA: “Quality and quantity of ventilation should be evaluated on installation, regularly monitored (at least every 3 months), and re-evaluated whenever a change in local ventilation devices is made.”

ANSI/AIHA Z9.5: “A routing performance test shall be conducted on every fume hood at least annually or whenever a significant change has been made to the operational characteristics of the system”

NFPA 45: “When installed or modified and as at least annually thereafter, laboratory hoods, laboratory hood exhaust systems, and laboratory special exhaust systems shall be inspected and tested.”

NFPA 45: “Special use laboratory hoods and special use local exhaust systems shall be identified to indicate their intended use.” “A sign shall be affixed to each hood containing the following information from the last inspection: Inspection interval, Last inspection date, Average face velocity, location of fan that serves hood, Inspectors name. Exception: In lieu of a sign, a properly maintained log of all hoods giving the above information shall be deemed acceptable.”

4. Exhaust

The old expression “out of sight, out of mind” is often apt when discussing fume hood exhaust. Lab personnel rarely crawl up onto the roof to check out their exhaust fans and stacks. Knowing what the standards, rules and codes have to say on the exhaust can come in handy if you’re experiencing odors in the lab or if you’re considering a renovation or new facility.

ANSI/AIHA Z9.5: “Discharged in manner and location to avoid re-entry into the laboratory building or adjacent buildings at concentrations above 20% of the allowable concentrations inside the laboratory under any wind or atmospheric conditions.” Exhaust stack: “Be in a vertical up direction at a minimum of 10 feet above the adjacent roof line as so located with respect to opening and air intakes of the laboratory or adjacent buildings to avoid re-entry.”

NFPA 45: “Air exhausted from laboratory hoods and other special local exhaust systems shall not be re-circulated.” “Air from laboratory units and laboratory work areas in which chemicals are present shall be continuously discharged throughout systems maintained at a negative pressure relative to the pressure of normally occupied areas of the building.

If you have any questions feel free to give me, Bruce Ciloski, a call. You can reach me at 832.256.0014 or email me at bruce@laboratorydesign.com.