Assess

Airflow in Laboratories

Airflow patterns in lab spaces play an important role in determining the air velocities, air temperatures, and concentration of contaminants which subsequently determine occupant thermal comfort and indoor air quality. Optimizing the flow path can help improve the ventilation effectiveness which can lead to safe, energy efficient, and sustainable laboratories. Unfortunately, lab ventilation systems can be complex, making it difficult to visualize the flow path of air and the resulting flow path of contaminants.

In general, clean supply air should sweep across the space and out exhaust paths, clearing airborne contaminants effectively from the space without significant recirculation or stagnation.

The airflow path can depend on several inter-related factors including:

• Supply airflow rate or air changes per hour (ACH)
• Contaminant type, location, and rate of generation (especially important in the case of ventilation-dominated laboratories)
• Type, location, and quantity of supply diffusers
• Quantity and location of exhaust grilles
• Location and intensity of various heat sources (especially important in the case of cooling-load-dominated laboratories)
• Location and size of exposure control devices (ECDs) (e.g. fume hoods—especially important in the case of fume hood-dominated ventilation)
• Arrangement of furniture and other airflow obstructions.

Specific airflow requirements are key in determining laboratory airflow specifications, including requirements for:

• Effective operation of ECDs
• Occupant comfort
• Maintenance of required differential pressure between adjacent spaces
• Maintenance of required air change rate.

The minimum amount of air flow in a lab is often defined in air changes per hour (ACH). Traditional design practices often claim higher ACH are better than lower ACH. However, recent studies have indicated that the pattern of air flow in the lab can be more important than the volume of air when trying to minimize occupant exposure [1]. Past specifications for ACH ranged from 4 to 12 for all labs on a campus, while various codes and standards will recommend different values. The 2012 ANSI/AIHA/ASSE/ Z9.5 standard requires that each lab's ACH be established independently based on risk to account for wide diversity in airflow requirements between different labs.

The system can be either constant-volume, variable air volume (VAV), or a combination. VAV systems are recommended for their energy and cost benefits; however, a mix of VAV and constant-volume systems may be a solution for specific facilities.

Variable Air Volume Systems	Constant Volume Systems
Modulate flow to satisfy the demand for ventilation Save substantial amounts of energy over lifetime More economical over time, especially when integrated in manifold systems Provide opportunity for continuous monitoring Require more complex supply and exhaust systems and additional controls Can be difficult to maintain Higher initial cost	Provide a constant flow to satisfy maximum demand Less expensive initially Less complex supply and exhaust systems Generally simpler to maintain over time Waste significant amounts of energy in times of minimal occupancy Higher cost of operation overtime due to inefficiency Additional effort required to implement analytics and continuous monitoring

The first step to assessing the laboratory's systems is to coordinate with operations and research staff. Engaging with the appropriate staff will assist in gathering building documentation, pre-survey questionnaires, and surveys of lab spaces and systems. Positive relationships with key laboratory personnel are crucial to ongoing maintenance, analytics practices, and dynamic optimization of lab ventilation systems.

Gather Building Documentation

The first step to assessing the laboratory's systems is to collect building documentation. Typical building design and operating documents include:

• Architectural floor plans showing labs, major ventilation devices, and energy consuming equipment
• Mechanical HVAC plans
• Testing and Balancing (TAB) and commissioning reports
• Current airflow control setpoints and sequences from the building automation system (BAS)
• Organization's Laboratory Building Design Guide
• Description of the systems and components that comprise each individual mechanical system
• Description of the control systems, including tables of setpoints corresponding to the system diagrams and summary of known operating sequences that affect modulation and control
• As-built system line diagrams, showing discrete systems including fans, ducts, controls, and devices
• Hazard inventory and waste records
• EH&S records.

Review available building documentation in advance of the field survey so that each space can be effectively, efficiently, and safely assessed.

Inventory Hazardous Chemicals

In collecting a hazardous chemical inventory, gather Safety Data Sheets and document how each chemical is used and disposed of. Once a detailed inventory is created, complete the following:

• Submit a chemical inventory for the building by hazard class to building officials
• Compare the inventory with building code maximum allowable quantities (MAQs).

Conduct a Pre-Survey Questionnaire

Before starting to survey lab and support spaces, it is important to get input from research staff and operations personnel about the workspace. Questions about work performed in each lab space, including procedures, personal protective equipment, and ECDs used will be helpful in orienting the surveyor as to what to expect during the survey. Examples of questions to include in the questionnaire include:

• How would you rate the safety of your lab work environment?
• What hazards and risks are acknowledged through standard operating procedures and protective equipment requirements? Are there additional hazards or risks associated with your research that you believe should be better mitigated?
• What ways can your lab improve practices to minimize exposure to hazards?
• Identify chemicals hazardous by inhalation.
• Describe lab activities that may cause inhalation exposure.

Set Boundaries for Lab Space Visits

Lab spaces are dynamic spaces that often host cutting-edge research involving hazardous situations that require special protective equipment. In conversations with researchers and operations personnel, set boundaries for lab space visits, including:

• When to conduct the walkthrough survey of lab and support facilities so as not to infringe on research productivity
• Where access to certain areas or photography may be prohibited
• What personal protective equipment (PPE) or special permissions may be required to survey each lab space.

See more in the Working with Scientists section.

Survey Labs and Support Spaces to Evaluate Risk

The LVRA survey should be performed by a qualified individual—such as facilities or EH&S professionals—with knowledge of mechanical ventilation, core sciences, and occupational safety and health. It is recommended that LVRA findings and conclusions be reviewed by a licensed Professional Engineer and/or Certified Industrial Hygienist prior to implementation of any recommendations. To guide the survey of labs and assigning risk levels, refer to the LVRA User Guide and the LVRA tool.

Surveys are conducted via site walkthroughs that include observation of general laboratory conditions. For each lab space, data collection for both ECDs and laboratory environments consists of three steps:

1. Description of ECDs or laboratory (i.e. type, size, access, monitoring)
2. Evaluation of the device or lab space purpose, condition, and processes
3. Assessment of the risk using determined criteria and rating presented below.

Data should be collected and recorded separately for ECDs and laboratory environment based on the following assessment categories:

• Type of hazards and procedures
• Generation characteristics of each hazard (method of generation, nature of hazard generated [e.g., gas, vapor, dust], potential for generation, etc.)
• Quantity of materials used or generated during lab procedures
• Frequency and duration of hazard generation
• Containment by ECDs (i.e. specific types, uses, and appropriateness).

Assessments in these categories inform ratings that are ranked by risk level, or risk control band (RCB):

Risk Level	Description
0	Negligible
1	Low
2	Moderate
3	High
4	Extreme

Data Collection for Exposure Control Devices

For each ECD in the space, perform the following data collection activities:

• Assign a unique identification number.
• Describe how the device is ducted, filtered, mounted, and document other identifiers.
• Examine location relative to other ventilation components.
• Conduct performance tests for all ECDs.
• Evaluate appropriateness of ECDs using the rating metrics provided below.

Data Collection for Laboratory Environment

Data collection for the laboratory environment survey follows a similar 3-step process as that of the ECD survey to evaluate risk. However, some differences are important to note. While the ECD survey focuses on effectiveness of hazard containment, the lab environment survey focuses on the directional sweeping of air across the workspace to remove contaminants.

Assign Risk Levels to Each Lab Space

The laboratory ventilation risk assessment process utilizes control bands to facilitate categorization of risk for laboratory spaces, fume hoods, and other ECDs. RCB categories provide a range for assignation of risk from negligible risk of exposure to airborne hazards generated during laboratory scale procedures (RCB-0) to extreme risk of exposure (RCB-4). Each RCB is associated with a hazard emission scenario that is used to recommend exposure control measures and derive operating specifications (airflow) for the laboratory fume hoods and HVAC systems serving the laboratories. Ventilated ECDs and spaces with higher RCB ratings require higher volumes of airflow with devices and spaces assigned lower RCB ratings require less air to meet the functional requirements of the ECDs and lab occupants.

The laboratory ventilation risk assessment provides a target of operation. System testing should be performed to establish a baseline of current operation, functionality, and boundary conditions of the ventilation systems. A comparison of the current operation baseline and the target operation identified in the LVRA will allow the team to identify improvement measures.

These tests will continue to be used for the Laboratory Ventilation Management Program (LVMP) to verify proper system operation and performance, and it is important to perform them correctly to gain accurate metrics for gauging improvement.

System testing falls into three basic categories:

Calculate Airflow and Operating Specifications

The demand for ventilation establishes the current airflow requirements that can be used to design systems or compare how the systems are currently operating. Quantifying demand for ventilation enables evaluation of the potential for flow reduction and energy conservation. Airflow specifications should be tracked in an airflow spreadsheet. Documenting, recording, and managing airflow specifications is a critical component of an LVMP. Changes to airflows for laboratories or ventilated ECDs resulting from changes in demand (i.e. physical changes or changes to processes conducted in the labs or devices) must be reflected in the airflow spreadsheet to reflect current conditions.

Refer to the Lab Ventilation Risk Assessment (LVRA) Tool in determining what air changes are required for given risk level in the lab environment.

Air Supply Flow

It is a common design practice to supply labs with 100% outdoor air to ensure a clean supply of air for conditioning and pressure control. Modern designs now utilize more transfer air from non-lab spaces to satisfy a portion of the air requirements for conditioning and pressure control, while maintaining safe lab environments.

The location and type of supply diffusers are important design characteristics. Good design practice places the supply diffusers away from fume hoods and general exhaust to maximize the utility of the condition air. At the same time, the locations should minimize air mixing and promote flow directly to general exhaust or exhausted devices. Diffuser design should supply air with low velocity and no induction of lab air. These attributes enhance ventilation and create opportunities to reduce lab ACH.

Exhaust Flow and Stack Discharge

Exhaust systems are vital to a lab HVAC system. Properly designed, constructed, and operated ventilation systems effectively:

• Remove airborne hazards contained by ECDs from the lab space
• Mitigate environmental contamination
• Reduce risk of exposure to hazards for maintenance and construction personnel
• Prevent re-entrainment of contaminants into occupied spaces.

Exhaust systems can be a large initial and ongoing investment. An exhaust dispersion assessment helps to minimize waste by analyzing the system and defining the flow requirements so that each exhaust fan can run at less than 100% load while still maintaining good air quality and compliance with ANSI/AIHA Standard Z9.5-2012, which provides guidelines for designing and operating lab ventilation systems.

Per ANSI/AIHA Z9.5, exhaust fans serving laboratories shall be adequately sized to provide the necessary amount of exhaust airflow, enough to maintain both the required exhaust airflow and stack exit velocity and the necessary negative static pressure (i.e. suction) in all parts of the exhaust system. Specifically, the exhaust stack discharge shall meet the following criteria from the ANSI/AIHA Z9.5 standard:

• Any exhaust discharge shall be a minimum of 10ft (3m) above adjacent roof lines and air intakes and in a vertical up direction
• Exhaust stack discharge velocity shall be at least 3000 ft/min (15.2 m/s), unless it can be demonstrated that a specific design meets the dilution criteria necessary to reduce the concentration of hazardous materials in the exhaust to safe levels at all potential receptors.

Emissions from external sources that may be re-ingested into the building between the building's exhaust stacks and air intakes are often overlooked in indoor air quality. Dispersion modeling predicts the amount of fume re-entry, or the concentration levels expected at critical receptor locations, with the goal of defining a "good" exhaust and intake design that limits concentrations below an established design criterion.

Refer to the hazard dilution calculator for determining the dilution of airborne hazards in different emission scenarios.

Coordinate with operations staff to gather information on:

1. Types of water sources used:
   • Potable
   • Non-potable
   • Onsite alternative water, such as rainwater or gray water
   • Purchased reclaimed water from wastewater treatment plant.
2. Data from water bills and logbooks from metered and sub-metered water sources to get a baseline of seasonal trends, including:
   • Quantity of each water source
   • Cost of each water source

Perform a Water Audit Survey

1. Conduct a tour of the facility to inventory all major water-using fixtures, equipment, systems, and processes.
   • Be sure to capture enough detail on processes to determine how much water is consumed by each end use.
   • Pay attention to drain lines plumbed to floor drains in building mechanical and utility spaces. Trace these drain lines back to the originating equipment to make sure they are included in the inventory.
   • Identify locations of all meters and submeters—read the meters and submeters, and check that the units and scale of the readings match water bills and internal logbooks.
   • Use survey forms or checklists, such as the Existing Plumbing Equipment and Water Use Inventory Worksheets provided by EPA WaterSense. This information will be useful in calculating the facility's total water use.
2. Interview any personnel that manage water-using systems or equipment to understand how the systems and equipment are operated and maintained and to verify water use. Be sure to record the hours of operation for each system or fixture to more accurately calculate water use over time.

Establish a water use baseline

To develop a water use baseline, consider the following activities.

1. Document lab's water use history using the water bills gathered from one or two years prior using a form such as the Water Consumption History Worksheet or a tool such as ENERGY STAR Portfolio Manager.
2. Calculate the facility's total annual water use. The facility water balance is an accounting of all water uses at the facility.
   • Metered or sub metered sources: Calculate typical annual water use from meter readings, water bills, or internal logbooks for identified fixtures, equipment, systems, and processes.
   • Unmetered sources: Estimate the annual water use from flow rate measurements collected during the facility tour (if available) or use equipment specifications and patterns of use. Consult the tools provided by the WaterSense program to help develop water use estimates for specific fixtures or equipment.

Based on the results of the water audit, compare the water use baseline with water use reduction goals. This will inform improvement measures to include in the scope of work. For guidance on best practices surrounding water-intensive research equipment, refer to the Equipment Specific Practices section on the Working with Scientists page.

Common Areas of Improvement in Water Efficiency

A laboratory's water efficiency can be improved by making a few changes in other types of equipment as well, as described in the I²SL Water Efficiency Guide for Laboratories.

Alternative Water Sources

Alternative water sources such as rainwater and gray water can often be effectively integrated into a laboratory's operations. Be sure to check with state and local regulations concerning alternative water use. More information on potential alternative water sources that may be available in the area can be found through FEMP Alternative Water Sources Maps.

Are there specific vulnerabilities at the site that should be addressed in tandem with Smart Labs projects?

Exploring vulnerabilities among multiple stakeholders is augmented by the work completed through the baselining exercises by jurisdictions and governmental entities. Outcomes from these activities provide a foundation for understanding each jurisdiction's vulnerabilities. These could include system shocks, stressors, natural or technological hazards, threats, or human-caused incidents. These are detailed further as potential vulnerabilities:

• Natural hazards, resulting from acts of nature and severe weather (e.g., severe winter storm, floods, earthquakes, hurricanes, solar flares, etc.)
• Technological hazards, resulting from accidents or system and structural failures (e.g., bridge collapse, grid outage)
• Human-caused incidents, resulting from threats or intentional actions of an adversary (e.g., cybersecurity threats, acts of terror).

Additional vulnerabilities may include longer term system stress posed by conditions such as population change and changing economic conditions. However, the focus centers on the short- and long-term hazards of potential threats and their impacts on infrastructure vulnerability.

Risk Assessment

Safety of the most vital assets of your organization – the researchers and staff – is of primary importance when conducting cutting-edge science. All risks and associated controls to mitigate should be documented. When assessing risks in the lab spaces, here is a starting point for what questions to ask.

• What are the risks? Understand if there is PPE required for each risk.
• Who has access to lab spaces where risks are present? Only employees who have been trained to work in a specific lab space should be allowed to access the lab unless they are escorted by trained employee.
• How will risks be mitigated? Typical risks may include:
  • Ventilation risk from chemical use or other airborne hazards
  • Electrical hazards
  • Compressed gases and liquids
  • Radiation exposure, including lasers.

In assessing the risks, be sure to talk with the scientists, as discussed on the Working with Scientists page. They know their work better than anyone and will be a good resource in assessing the risks that are present in each lab space. However, scientists should not be the only resource. Be sure to supplement understanding through discussions with other professionals such as industrial hygienists and research support staff.

A wide range of measures can improve electricity assets and systems' resilience to climate impacts. These measures include making physical and structural improvements to "harden" the system components as well as planning and modifying operations to build resilience. Strategies for mitigating impact in the event of unforeseen events are described below.