UTFRG Standard Operating Guide

I. Safety

The number one priority in each laboratory is safety! It is the responsibility of each student to ensure that conditions in the laboratory are safe for those running an experiment and those around him/her.  Normal lab times are between 9 AM and 5 PM.  Experiments should not be run outside of these times without the prior approval of Dr. Ezekoye.

Training

Before you can work in the UT Fire Research Group Lab you should take the lab safety courses (OH 101 and OH 201) offered by Environmental Health & Safety. The links for these courses are found at:

https://www.utexas.edu/safety/ehs/train/courses.html#oh101

OH 101: OH 101 — Hazard Communication (EID required)

OH 201 OH 201 — Laboratory Safety (EID required)

Electrical hazards can occur when you put together your own circuit to run an experiment.  It is a good idea to get a sanity check from an expert. See Mark Philips in the ME electrical shop if you have any questions about designing and using a circuit.

A clean and well organized laboratory is the first step to maintaining a safe laboratory. It is best to have a regular location for everything. Clean up spills immediately. Throw away scraps of material. Store equipment that is not of immediate use.  All tools should be neatly put away each evening.

Machine Shop

All students should take the instructional course offered by the machine shop. This one day course is offered several times each semester and is required before you are allowed to use any of the equipment in the shop. See Ricardo Palacios (ETC 1.214) to sign up.

II Handling Fuels & Other Fluids

Gas Bottles

All cylinders containing compressed gases must be tied down at all times to prevent them from falling over. If a valve is knocked off of a gas bottle you have a rocket in the lab! When changing a bottle, remove the regulator and screw the cap over the valve. Use a cylinder cart to move it. Each type of gas has its own type of regulator and regulator fitting. Consult the Matheson catalog for the regulator and the number of the fitting you need. When turning on a gas bottle never open the valve to full open such that it is tight in the CCW direction; someone may try to close the valve and assume it is already closed. Some gases, particularly flammable gases, have left-hand threads on the fitting that connects the regulator to the bottle valve, watch for this! Our current preferred vendor of gas bottles is Airgas.

Natural Gas Lines:

The building has low pressure natural gas lines. They are a convenient and inexpensive source of natural gas, however, their usefulness is limited because they are very low pressure (in the range of inches of water). The pressure is too low to be used with a pressure regulator, but it is sufficient for a Bunsen burner. Care must be taken to ensure that these are not left open; the pressure is not high enough to create a blowing sound that you can hear. Any use of the natural gas should be done under an operating exhaust hood.

Flame Arrestors:

Flame arrestors are devices used in flow lines to prevent a flame from propagating up the line. They should be used in lines where a premixed flammable mixture of fuel and air is flowing from a mixing chamber to a burner.

Flammable Liquids:

We use several flammable liquids in the labs including: heptane, methanol, acetone, and gasoline. Only small amounts (less than a gallon should ever be in the building at any time. There is a yellow flammable liquids in 10.102A.  Fuel containers should always be capped except during use. If the fuel is to be sprayed under pressure from a pressurized container, it is advisable to use an inert gas such as nitrogen to pressurize it.

III.  Personal Protective Equipment (PPE)

There is a shelf dedicated to PPE in the main lab area of 10.102A.  You will find latex gloves, breathing masks, eye protection, and work gloves in this space.

Hazardous Liquids:

Care must be taken when handling hazardous liquids such as concentrated acids or titanium tetrachloride. Gloves and a face shield should always be worn. The dangers associated with the handling of methanol and acetone are not clear, but they can be hazardous. To be safe, it is probably best to avoid getting these liquids on your skin.

Aerosols/ Airborne Particulates

Again the hazards associated with breathing aerosols (airborne particulates) are not well known, but it is a good safety practice to wear a breathing mask when handling particles (e.g., aerosol silica used to make drywater) or particle generating items such as alumina boards, cutting gypsum boards, or insulation samples. 

Use of Hoods:

Whenever an experiment is run that requires the flow of anything other than air or water vapor, the exhaust should always be directed into a ventilation hood. Most of our hoods have a large flow capacity, but you should be sure that it is drawing enough. Always check to ensure that the hood is turned on, and is drawing before starting and experiment. If the hood sash is open more than 18 inches an alarm will trigger.  Close the hood sash to stop the alarm.

Lasers:

When using lasers proper laser eye goggles should be worn. An experiment should be set up such that the beams are kept in a plane below eye level, and beam blocks should be used to keep beam reflections from leaving the optical table. Lasers should not be operated without their covers on; the high voltages inside are potentially deadly.

IV. Purchasing

Purchasing items needed to conduct your research can be a complicated matter. The procedure depends upon what you need, and how quickly you need it. For items under $999, use the PROCARD.  You should have gone through the PROCARD training.  The purchases must be tax exempt. More information about the pruchasing process can be found in Purchasing.   

A Tax Exempt Form is on this wiki in the File List.

V. Travel 

Business Travel

Here are the pertinent links: 

RTA (Request for Travel Authorization)  Form: https://www.ece.utexas.edu/services/forms/request-travel-rta

Point of Contact: Esther Orsborn at esther.orsborn@austin.utexas.edu 

UT Travel Page: http://www.utexas.edu/travel/

Concur (UT's Travel Reservation Tool): https://www.concursolutions.com/home.asp 

More information can be found in Business Travel 

Vacation Travel

For personal travel, the UTFRG vacation travel policy is outlined in the travel policy document.

VI .   Conducting Experiments

Each student conducting experiments should have a laboratory notebook. Each time lab work is conducted, the important or relevant facts should be recorded along with the date. The information recorded should include a complete list of operating conditions, and all information necessary to repeat the experiment and analyze or process the data. The quality of a calibration the data should be ensured through a proper uncertainty analysis and through your ability to obtain repeatable results.

Tips for experimentalists

It's not easy to be a good experimentalist. In addition to everything else, it requires a body of knowledge that you usually don't learn in class. This may include anything from the theory of operation of a specific piece of equipment to how to order a part. One of the best resources for the new student is the more advanced students who already "know the ropes." Don't hesitate to get help or to give help to each other.

Every student should try to advance his/her research as efficiently as possible in terms of both time and money. It is usually the case, especially for experimentalists, that there are many tasks which need to be accomplished. Learn to work in parallel on your various tasks. Often you will need to order something for your experiment. While you are waiting for it to come, work on some other aspects of the experiment. If stymied on all other fronts you can still study the literature.

A thorough knowledge of the literature in your area is essential. Often the hardest part of a literature survey is finding the first good relevant paper. Once you find this one, it will contain other references which you can look up, that will lead you to still further references.

Scavenging

Another very important way to save both time and money is by scavenging. There is a lot of old general purpose equipment and materials in every laboratory. A good experimentalist is a good scavenger, and knows the contents of every drawer and cabinet in his/her lab. Another good resource is the scrap metal box in the basement of ETC.

Tubing and Piping

Almost all of our experiments use flows of air, fuels, and/or water. This means installing lines and pipe and tube fittings. The materials you choose for these lines depend upon the fluid and the working pressure and temperature.

Lines for air and water that will not see temperatures above  room temperature nor pressures above 100 psi can be made of plastic (polyethylene) Plastic is often the most convenient because it is flexible, easy to cut, and inexpensive. Smaller diameter plastic tubing (1/2 in. O.D. and smaller) is coupled using Swagelok fittings. The larger diameters are usually coupled to pipes using hose clamps. The large plastic tubing is available from the Chem. Stores. Plastic tubing is not to be used with fuels.

Copper tubing can be used for cooling water flows and for some fuel flows. It is flexible and will resist high temperatures. It is cut using a standard tubing cutter.

Stainless tubing is to be used for severe operations, where combustion temperatures or high pressures are expected, or with corrosive fluids or environments. It is very stiff. This can be an advantage in certain applications where the line can serve as a support member. Stainless, however, is expensive and difficult to work with.. Both copper and stainless steel tubing should be bent using a tubing bender.

For air flows in excess of about 200 1pm, standard plumbing type pipe is recommended. We usually use brass pipe and fittings, however, the larger diameters (> 1 in. NPT) are usually only available in cast iron.

Swagelok and Pipe fittings

We use two different types of fittings: Swagelok tube fitting and pipe thread fittings. Almost all of the lines we use for fluid flow use both tube and pipe fittings.

Tube fittings are used with tubing, and are sized according to the actual outside diameter O.D. of the tubing. The type of fitting we use for tubes are Swagelok fittings (Tradename). A competitor (Gyrolock) makes compatible fitting, but we usually use Swagelok.

To tighten an end of a piece of tubing in a Swagelok fitting, push the end into the fitting until it stops (about 3/8 to 1/2 inch) Tighten the nut on the fitting until finger tight and then turn it another 3/4 of a turn with a pair of wrenches. The tubing is held in place by two rings called ferrules (back ferrule and front ferrule) that are under the cap of the Swagelok nut. Once tightened, the ferrules are crimped unto the tube and can never be removed.

Do not use Teflon tape for sealing the threads on a Swagelok tubing connection; the ferrules make the seal. Almost all Swagelok fittings are available in either brass or stainless steel. The stainless is usually 4 or 5 time more expensive than brass, so buy brass unless dealing with very high temperatures or corrosive materials.

Pipe Fittings

Many Swagelok fittings combine tube fittings (Swagelok) with standard pipe thread fittings (NPT). Pipe threads are tapered threads (as opposed to straight treads which have a constant diameter) and are used on all common plumbing type pipes. They are sized in inches (followed by "NPT" which just means it's a pipe thread). Pipe threads are sized in a bizarre way such that the actual diameter of the thread is much larger than its size designation. The most common pipe thread sizes we use are probably 1/8 in. NPT and 1/4 in. NPT A 1/4 in NPT thread, for example, has a diameter of approximately 1/2 in. The only way to determine the size of a pipe thread is to compare it with a known sample.

Teflon tape is usually used to seal pipe threads less than about 1/2 in. NPT. Above this size a goopy liquid pipe sealant is usually recommended.

ETC  Building Compressed Air, Filters, and Regulators

The house compressed air is very convenient since it is available in most of the labs. The pressure at the wall is typically 100 psi. Usually, a working pressure lower than this is desired. This means installing a pressure regulator that will allow you to adjust the delivered pressure to whatever lower value is desired. The house air is relatively dirty; it contains water and oil from the compressor. Because of this a filter is usually installed upstream of the regulator. You should size the regulator based upon the expected maximum air flow rate in cfm and upon the most convenient pipe thread size for the inlet and exit ports. If you have any problems with the operation of any of the building facilities such as the hoods, compresses gas lines, or water lines talk to Fred Rothhauser or Danny Jares in the ETC shop.

Flow Measuring Devices

In most cases you will want to quantitatively measure the flow rates you are dealing with so that you can determine equivalence ratios, mean velocities, energy input rates, etc. To do this you must choose a type of flow meter, and then calibrate it.

Liquid flows

Liquid flows typically include flows of cooling water and flow rates of liquid fuels. The flow rate of a liquid is usually monitored with either a pressure gauge or a rotometer as the indicating device. The device is usually calibrated by setting the pressure gauge or rotometer to a given setting and then collecting the liquid in a graduated cylinder for a fixed time, measured with a stop watch.

Liquids to be delivered by a high pressure spray nozzle are usually monitored with a pressure gauge. Low pressure liquid flows are usually measured with rotometers.

Gaseous Flows

We use several different metering devices for gas flow measurement and calibration. Gas flow meters are typically more difficult to calibrate than liquid flow devices because you can't simply catch the fluid in a bucket.

The most common metering devices we use are rotometers and thermal mass flow meters. The device you choose depends upon several things. Both devices are available in sizes that cover the range of flow rates we typically deal with. Cost is a major consideration.

Thermal mass flow meters and controllers are rather expensive. The elements are typically about $1000.00 each and the readout boxes, which handle about 4 elements are about $1000.00; Hastings Corp. is a source of many of our mass flow meters and controllers. Rotometers are typically about $160.00 for air flow rates below 601pm. Rotometers for flows above this range (perhaps up to 600 1pm) are usually $400. to $500. Cole Parmer is a typical source for these. Matheson and Omega also sell flow meters.

Mass Flow Meters and Controllers

Mass flow meters and controllers are convenient because they are electronic; you look at an LED display for a direct indication of the flow rate. They work on the principal that a small heated wire in the meter is cooled by the flow of gas, the higher the flow rate the greater the cooling rate. As the wire is cooled, its resistance changes, detecting the flow rate. There are mass flow meters, which simple indicate the flow rate, and there are mass flow controllers which allow you to turn a knob on the electronic control box and set a desired flow rate. A mass flow controller has a built in solenoid valve and uses a feedback control system to maintain a constant mass flow rate, supposedly compensating for temperature and pressure fluctuations. Flow controllers can be very convenient, but they can also be problematic. They tend to have stability problems that cause them to pulse the flow rate slightly, or "hunt". In my experience they also tend to lose their calibration more quickly than rotometers. To maintain the best calibration it is best to leave them turned on all of the time.

Rotometers

When calibrated properly, rotometers can be as accurate, or more accurate than thermal mass flow meters. For gases, care must be taken during calibration, that the pressure downstream of the rotometer is the same as in the actual experiment. This is because the downstream pressure determines the density of the gas in the tube of the rotometer and, hence, the drag on the float. Read the scale of a Rotometer from the widest part of the float; this means from the center of the ball for small meters and the from widest part of the conical part of the float on large rotometers.

Calibration of Flow Meters used for Gases

There are two types of devices we commonly use to calibrate our gas flow meters. For very small flow rates (approximately 3 1pm and less the most accurate standard is the Brooks Volumeter. This is a glass cylinder that contains a Teflon piston which is sealed with a ring of mercury. This is a very accurate positive displacement meter. A flow meter is calibrated by attaching a line from the exit of the flow meter to the inlet tube of the Brooks meter. There is a valve on the meter that allows the flow to enter the meter causing the piston to rise. The scale on the side of the glass cylinder is calibrated in liters. A stop watch is then used to measure the amount of time it takes the piston to move a distance equivalent to several liters.  See Dr. Hall to borrow the Brooks Volumeter.  For higher flow rates, the engines group has bellows flow meters.

Pressure transducers

Computers & data acquisition

Heat Flux Gages

Thermocouples

Anemometers

Furnaces

Acoustic Transducers

Mass Loss Cone

Gas Chromatograph

Burn Structure (see the safety sheet Burn Structure and Fire Experiments)

Computations and Software

FDS (see Fire Dynamics Simulator)

CFAST

Phoenix SVN Repository (see Using the Phoenix Subversion Repository)

The Barn (see The Barn - Large File Storage)

Ipython Notebook (see Using Python/NumPy/SciPy)

Matlab

R

Papers, Reports, and Posters

Latex

Bibliographical Databases

Mendeley