11. Basic Tools, Instrumentation, and Equipment

Many of the functional tests in the CTPL contain a list of the tools, instruments, and equipment necessary to perform the test. In addition, the Functional Testing Field Tips table in each chapter of the Functional Test Guide lists the instruments and tools typically required to perform the tests associated with the topic of discussion in the chapter. The tools in the following list are basic tools that you will probably need in the course of commissioning a project, regardless of the testing to be performed. They are broken into two categories: essential and desirable. The tools in the essential list are strongly recommended for any basic tool set for commissioning work. The tools listed as desirable would make good additions to the essential tool set as funding becomes available.

These lists are just starting points and are by no means comprehensive. The longer you work as a commissioning provider, the more you will find that your tool and equipment set grows and adjusts to accommodate your personal needs and preferences. In any case, having your own tools and equipment offers advantages over borrowing the things that you need from others working on the project site.

1   You can make sure that you have what you need when you need it.

2   You will have direct knowledge of the accuracy, capabilities, and limitations of your instruments. This knowledge can be important in evaluating the information you gather.

3   You will have with you what you consider to be the right tools for the job.

Essential Tools, Instrumentation, and Equipment

·       Hand tools: A good set of hand tools includes an assortment of wrenches, screwdrivers, pliers, wire cutters, wire strippers, channel locks, punches, hammers and other common hand tools. These tools are especially useful in a retro-commissioning environment where it is unlikely that there will be tradesmen available with the tools that you need.

Figure 4: Storage type clipboard

·       Flashlights: Having both a large flashlight and a mini flashlight is essential. The mini flashlight will serve for most purposes, but the larger light can be useful for inspections above ceiling spaces or other areas.

·       Clipboard: Having a clipboard is important to provide a portable writing surface as well as a way to hold on to notes and test procedures. For a little extra money, you can get one with a storage compartment that provides a convenient way to carry some of your other equipment around on the site with you (Figure 4).

·       Safety Equipment: Hard hats, safety glasses, ear protectors, and steel-toe shoes are generally good ideas on construction sites and around machinery and may be mandatory at some locations.

·       Calculator or Slide Rule: Having a small pocket calculator available makes quick field estimates easy to accomplish. Having a slide rule means you can do the same thing without batteries.

·       Psychrometric Chart, Tables, and Other References: Access to a psychrometric chart makes analyzing an HVAC process easier to accomplish in the field. Having some pocket hand books and frequently used tables can also be useful for helping you solve problems in the field as they occur. Useful references might include:

·       The ASHRAE Pocket Handbook and similar handbooks by other professional organizations

·       Steam tables

·       Refrigerant tables

·       A list with frequently used equations, formulas and units conversion factors

·       Tables of pressure loss factors for common duct and pipe fittings

·       Small scale floor plans of the building you are working in

Laminating these papers will make them more durable in the field and will also allow you to draw and erase using a wax pen or crayon.

·       Multi Tool: A folding multiple tool device, like a Leatherman or a Gerber Tool, can come in handy in the field. Just remember to take it off your belt and put it in your checked luggage before going through airport security on your way home.

·       Camera: Documenting existing conditions and problems with a camera can be a real time saver and memory jogger. Digital cameras have the advantage of providing an instantaneous picture that can inserted in reports and e-mail. Some commissioning providers use a digital camera plugged into a laptop logged into the Internet to witness pressure tests or observe operating conditions from a remote location.

·       Indelible Markers:Several “write on anything” markers in different colors can be useful for marking sensor locations on pipes and ducts. Soap stones and white grease pencils are useful for making sensing port locations on black iron pipe.

·       Jeweler’s Screw Drivers:A set of small screw drivers with different blade styles and sizes can be useful for working on control system components for calibration and other adjustments as well as working with small terminal strips.

Figure 5: Duct Test Port

(Image courtesy of the Vent Fabrics web site)

·       Drill and Drill Bits, Hole Plugs: A rechargeable, portable electric drill is useful in the field to make holes in ducts for measuring air flows and temperatures. Hole plugs in the form of rubber stoppers or sheet metal caps seal your test ports when you are done. (Figure 5)

·       Duct Tape and Silicon Sealant: Both of these products can be handy for temporarily sealing test openings created in a duct system or for repairing the vapor barrier on insulation when it is broken by a test port penetration. They need to be used with caution in some process environments however. The off-gassing from the silicon sealant can create quality control problems for some clean room processes.

Figure 6: Lab grade thermometers

Note the 2/10 degree scaling marks. (Image courtesy of the Fisher Scientific web site)

·       Tape Measure and 6 Foot Folding Ruler: Having at least one of these measuring tools is nearly mandatory. Having one of each can be handy for taking measurements in different situations.

·       Electrical Meters: Having a small portable multimeter and an amprobe available can allow valuable troubleshooting information to be readily obtained. In inexpensive pocket multimeter has the advantage of portability. However, a larger, higher precision meter can be useful for cross checking calibration and input signals on control systems.

·       Lab Grade Thermometers: Electronic thermometers win the contest in terms of ease of use, durability, and cost, but it’s hard to argue with a lab grade fluid in glass thermometer. There are no batteries to fail and no calibration adjustments to make. Thermometers for several common temperature ranges can be useful for providing a baseline for a relative calibration test or troubleshooting. Pairs of thermometers in common ranges can provide a good way to document temperature changes across heat transfer elements. Mercury thermometers were the original instruments of choice in this category, but with the growing concern over hazardous waste, thermometers using other liquids are becoming popular because if they break, they do not pose a contamination problem. If you purchase these devices, it’s a good idea to make some carrying cases for them out of PVC pipe large enough to accommodate the thermometer encased in a layer of bubble wrap.

·       Sling Psychrometer: While somewhat harder to use than an electronic hygrometer, a sling psychrometer will provide a reliable measure of wet bulb temperature. The instrument uses mercury thermometers so there is never a need to change batteries or calibrate. Be careful not to swing it into a wall or equipment housing. For tight quarters, units are available with a battery-powered fan.

·       Inclined Manometers: A set of inclined manometers and several different sized pitot tubes allow a variety of pressure and flow readings to be taken for a relatively low first cost. At least two meters should be obtained, one in the 0 to 1/4 inch water column range for low pressure readings and another in the 0 to 10” water column range for higher pressures. This is one instance where the advantages of the electronic versions of these instruments might outweigh the advantage of the inclined manometer measurement with no power supply required. However, the inclined manometers will usually cost significantly less than the electronic meter and offer a good compromise between price, flexibility, ease of use, and accuracy. The meter set should be supplemented with several static and pitot static probes. The probes come in a variety of lengths to allow ducts of all sizes to be traversed. The typical diameter is 1/4”, but short, flexible, smaller diameter probes are also available. These probes are useful where pressure relationships must be verified by sliding the probe under a door threshold or through the crack between the door and the jamb.

·       Precision Pressure Gauges: A set of high accuracy pressure gauges will be useful for measuring coil and valve pressure drops as well as performing pump tests. This is another area where the electronic version may provide better accuracy and flexibility, but at a cost premium. A set of two or three precision gauges may be more viable as an initial investment.

·       Backpack: A backpack is a convenient way to carry all of this equipment around. It allows you to keep both hands free yet have everything you need close at hand.

·       Pocket Tape Recorder: A small portable dictation type tape recorder can be a convenient way to gather nameplate data in the field or record observations. It also is a convenient way to take meeting minutes (be sure to tell everyone you are doing it first). A voice activated feature is especially convenient since it allows you to simply clip the mike to your shirt collar, slip the recorder in your pocket and make comments or document data as needed.

Figure 7: Portable anemometers

 

(Images courtesy of the PG&E Energy Center)

·       Anemometer: A rotating vane anemometer can be a convenient way to estimate low velocity air flows. Rough estimates of unit flow rates and minimum outdoor air flow rates can be obtained by taking velocity readings across filter banks or intake louvers with this device. The readings may not be exact, but they will be better than a guess. (Figure 7).

·       Tachometer: The speed at which shafts rotate can be a key indicator of performance. There are a variety of tachometer options available such as mechanical tachometers, digital tachometers, and strobes that allow the shaft speed to be measured without actually being in contact with the shaft. The strobe tachometer is generally the most expensive option, but it also is the most flexible and safest approach. When working with a strobe tachometer, it is important to remember that the strobe will freeze the shaft motion at the fundamental speed (the speed that you want to measure) as well as at its harmonics (even multiples of the speed you want to measure).

Figure 8 Tachometers

The instrument on the left must be in contact with the rotating shaft to measure rpm. The strobe on the right can be used for non-contact measurement by “freezing” the motion of the rotating element.

Taking shaft speed measurements will involve working in close proximity to rotating machinery and extreme caution should be exercised when taking these readings. Make sure that you do not have any items which could become entangled with the shaft and pull you into the machine. If possible, take shaft speed readings through the openings provided with the belt and shaft guards in place. If the motor and shaft are mounted internal to the fan casing, you need to be aware that if someone opens the access door to the unit while it is operating, there can be considerable wind pressure generated which can throw you off balance.

·       Dataloggers: Even though most current technology buildings are equipped with DDC systems that allow trending of the data required to commission the system, having several data loggers available with a variety of input sensors to supplement this capability can often be useful for the following reasons:

1   Proper commissioning or troubleshooting of some systems may require a sensing point that was not included with the DDC package. Using a datalogger available to pick up this information is often the quickest, least costly way to obtain the data.

2   Retro-commissioning applications in older buildings may involve working with non-DDC controlled systems. For these situations, portable dataloggers provide an economically feasible approach to obtaining trend data.

3   Most commercial DDC systems are restricted to a trending rate of 1 sample per minute or more. This is suitable for many applications, but can be a limitation for a identifying problems in some processes. Many dataloggers are capable of sampling at frequencies of once per second or more.

Figure 9: Data loggers

A wide variety of data logging equipment is available in the current market at modest cost. Capabilities range from small, dedicated purpose units like the loggers pictured to the left to multiple channel, programmable loggers like the unit pictured on the right.

Figure 10: Portable Datalogger Guide

This guide on portable dataloggers, along with other manuals outlining O&M best practices can be downloaded free of charge from www.peci.org/om.

The capability to log four temperatures, one or two amperages, and status of motors and lighting will allow a commissioning provider to address most of the common problems encountered in the field when the need exists to supplement existing DDC equipment or troubleshoot an isolated problem. Humidity and low and high range pressure logging capability can also be useful. In situations where multiple systems and parameters must be monitored, significantly more datalogging capacity will be required if there is not a DDC system available. If the commissioning provider does not have the datalogging capacity necessary, they can lease dataloggers and input sensors or purchase the additional dataloggers.

Most investments in current technology data logging will pay for themselves quickly in improved diagnostic capability, reduced trouble shooting labor, and more accurate energy savings projections.

Desirable Tools, Instrumentation, and Equipment

·       Shortridge or Other Electronic Air Data Multimeter: An electronic pressure measurement meter like the meters used by most balancing firms is an expensive but highly useful tool. Most meters of this type can measure pressures in the thousandths of an inch water column range accurately, and thus can detect and measure low velocity pressures and air flow rates. Typically, they have a variety of ranges and often will perform the calculation to convert a velocity pressure to velocity, allowing direct readings of velocity to be taken. They also can be purchased with a memory feature that allows multiple readings to be taken, stored and averaged allowing a pitot tube traverse to be made easily by one person.

Figure 11: Air Data Multimeter

(Image courtesy of the Shortridge Company)

·       Radios: For large projects or for tests requiring coordinating multiple parties at different locations, a set or even several sets of radios are invaluable. Generally, the more expensive radios are worth the extra money in terms of range and flexibility, especially inside buildings and on large projects where numerous people are using radios to communicate.

·       Personal Organizers: Personal organizers, like the Palm Pilot™, can be quite useful for commissioning providers and others working out in the field. At a minimum, having a ready reference for schedules, appointments and contacts can be useful. There are also numerous engineering applications available that can make life easier including units conversion programs and psychrometric programs.

·       Electronic Thermometer: Electronic thermometers are a rugged and easy approach to field temperature measurements. The accuracy will probably not be as good as a good lab grade thermometer, and this reduced accuracy should be kept in mind when taking readings. Many of these devices use thermocouples for inputs and the accuracy can easily be ±2° or more degrees. Accuracy will not matter for differential readings taken with the same meter or relative calibration work, but it may be significant in instances where absolute accuracy is important.

Figure 12: Electronic Hygrometer and Electronic Pressure Gauge

(Images courtesy of Omega Engineering and the PG&E Pacific) Energy Center)

·       Electronic Hygrometer: Electronic hygrometers offer a more rugged, faster way to take humidity measurements compared to a sling psychrometer. However, these devices may not offer the accuracy of a good sling psychrometer with matched liquid filled thermometers. Special equipment is often required to perform accurate calibrations of electronic hygrometers.

·       Electronic Pressure Gauge: Electronic pressure gauges often offer a more versatile approach to multiple range pressure measurements, but usually at a cost premium compared to precision bourdon tube type gauges. The electronic version most likely offers better accuracy than the mechanical version.

·       Dataloggers: As indicated previously, expanding your stock of dataloggers is desirable. Adding datalogging capacity or the ability to log different data sources will improve your ability to diagnose and correct problems in a timely fashion.

·       Signal generators, and Field Calibrators: In most instances, the calibration of sensors will be the responsibility of other parties. However, in a retro-commissioning or troubleshooting environment and in situations where calibrations need to be crosschecked, field calibrators can be a useful tool. In addition, having this type of calibration equipment will allow a true, multipoint calibration to be performed in the field.

Multi-function units frequently allow one instrument to simulate a variety of fairly standard functions, as shown in the upper left in Figure 13. Dedicated instruments, like the RTD calibrator shown in the upper right in Figure 13 may offer better precision or the ability to simulate many different variations of a particular device.

When using field calibrators and simulators, there is one important point to remember. Unless the simulator is simulating the measured parameter in a manner that subjects the entire sensing system to the simulation, then calibration to the simulated signal is only calibrating a portion of the system. For example, if a 4-20 ma field calibrator is installed in place of a duct mounted RTD with transmitter and the readings at the controller are adjusted based on the signals from the calibrator, then the calibration assumes that the information provided by the transmitter/RTD assembly is accurate. To improve upon this situation, an RTD simulator could be installed on the transmitter in place of the RTD. Now, adjustments made include any inaccuracies placed in the input by the transmitter. But, the process still assumes that the RTD is providing accurate information to the transmitter. Immersing the transmitter in a bath that subjects it to the required calibration temperatures (Figure 13 right picture) calibrates the entire system. Of course, the calibration will only be as good as the reference standard used to determine the bath temperature.

Figure 13: Field Calibration Equipment

A multiple function calibrator is shown in the upper left, a RTD calibrator in upper right, and a constant temperature dry bath at the bottom. (Images courtesy of Omega Engineering and the PG&E Pacific Energy Center)

  

·       Portable Folding Ladder: Having your own ladder will usually pay for itself in the long run because it can take a surprising amount of time to locate, borrow, and return a ladder on a construction site or in an existing facility.

·       Portable Folding Table And Chair: As a commissioning provider, you will find that you are working with manuals, drawings, binders, laptop computers, and other equipment on a frequent basis. Having a portable folding table and chair will allow you to quickly set up a temporary work area on a project site and get organized.

All tools should be used safely and with consideration for the labor practices at the job site. Work rules and trade practices can vary by location. You probably have found that at some sites there is a lot more latitude regarding how “hands on” you can be. These rules can also change when the project transitions from being owned by the contractor to being owned by the Owner. Finally, corporate safety plans and practices may restrict the amount of hands-on work that can be accomplished by someone who is not an employee of the company. For your own sake and the sake of safety and labor relations, always check on the rules and practices that are in effect on a site before diving into working on a machine with your tools.