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Hand Dryers vs. Paper Towels

Group 4 Keun-woo Lee Emily Lounder Nick Quintana Grace Xu
by

Keun-woo Lee

on 5 December 2012

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Transcript of Hand Dryers vs. Paper Towels

Conclusion Procedure Data Introduction
& Question Observations Installed in 3 bathrooms across campus (both boy’s bathrooms in A-Building and in the boy’s bathroom in C-Building).
Manufactured by Fastaire Hand Dryers, formerly Humphrey Inc, the Fastaire HD-03 models have a push-button start and an automatic cut-off after approximately 30 seconds.
According to the manufacturer, they have a voltage of 120 volts, a current of 7.5 amps, and a current cost of $420.
With a voltage of 120 and a current of 7.5, then the power should be around 900 watts.
Prices vary on online sources, and EPISD and the current manufacturer have no records of past market costs, like the cost when they were installed. Paper Towels
& Hand Dryers Hand Dryers:
Coronado High School uses more paper towels than it does hand dryers - which are more or less obsolete. In the long run, if CHS were to invest in replacing all paper towel dispensers and paper towels with newer, more efficient hand dryers, money saved in the future from continually buying paper towels would compensate for the expensive endeavor.Less trees would be wasted, less energy used if these hand dryers comply to Energy Star standards for energy efficiency. Proposed Solution Are hand dryers more efficient in comparison to traditional paper towel usage at Coronado High School? Question Since an average of 6-7 occupants used bathrooms with hand-dryers in each period, including the lunch period and transitions from 11:57 to 11:36, which factors in transition periods, approximately 60 boys visited each bathroom per day.
With a cut-off after 30 seconds and an average of 60 uses per day, the hand-dryers are used for 1800 seconds per day, or 30 minutes, assuming each user dries his hands with the hand-dryer. Every billing period (4 weeks) that amounts to approximately 600 minutes(20 school days * 30 minutes of usage/day) or ten hours of power usage.
Coronado High School falls under the general service rate for El Paso Electric (demand between 15kW and 600kW), and assuming that the school has peak demands of power 5 days/week in the nine hours between 7:30AM and 4:30PM, then 180kWh should be billed, according to 2012 El Paso Electric Schedule 24 for General Service Rate, at the first 200 hour rate of $0.06755 per kWh(summer rate). Calculations At those rates the cost of drying hands in the hand-dryer-equipped bathrooms amounts to approximately $0.61(.9kW*10 hours*$0.06755 per kWh) for a month for a single bathroom, and approximately $1.83 for all three bathrooms.
Assuming the original cost of the hand dryers is $420, then for a year following installation, at 1.83 $/month, the hand-dryers cost (approx. 9 months/school year) $436.37, not taking into account lower rates for winter.
The cost of supporting the paper towel supply in the other nineteen bathrooms is on average $92.11 per bathroom, or $276.33 for the three girl’s bathrooms observed compared to the $1.83 per month for the three bathrooms with hand-dryers.
Over a year, the cost of supplying paper towels for the three bathrooms in question will cost $828.99 (92.11 * 9 months). Using this cost and quantity information, we moved on to analyzing the effectiveness of the hand dryers.
Next, we went to every bathroom which contained a hand dryer and timed the each dryer’s performance.
We called the manufacturing company of the specific hand dryer models in in our school and acquired the electrical power information we needed to deduce how much electricity the dryers were using. In some of the boy’s restrooms, the school district has installed small hand-dryers in order to cut back on paper waste.
Hand dryers use electricity to blow a current of air. Electricity in the El Paso metropolitan area is generated in large part with the combustion of fossil fuels that affect the environment with the production of various gases. Efficiency of Paper Towels vs. Hand Dryers Firstly, we needed to gather some basic information on the logistics of paper towel supply in Coronado High School. We approached Mr. Joe Parra, Head Custodian of the school, and asked him several questions, such as:
How often are the paper towels replaced in the bathrooms?
How often are the towels ordered, how much is ordered at a time, and what is the average cost of supplies?
How long have the hand dryers been installed in the school, and how often do they require maintenance?
From this interview we acquired many receipts with order and cost information of the paper towels. In conclusion, we proved that our conjectured hypothesis was incorrect. From the data collected from the three bathrooms that we observed, our calculations showed that the hand dryers were far more cost effective and efficient than paper towels. Roughly speaking, factoring in the cost of the hand dryers themselves, the school pays on average of around ~$437 during nine month school year for the purchase and operation of the machine. Hypothesis If the hand dryers installed in the boy's bathrooms are outdated models utilizing large quantities of energy, then paper towel utilization for hand drying will be more efficient in terms of production costs including paper waste produced. Both paper towels and hand dryers have an environmental cost
Newer models of hand dryers are said to be more "green" once all factors of environmental friendliness are taken into account
Though there are several variables that can complicate the comparison such as how local power grids generate electricity and the vast variation in how paper towels are produced Identification of Variables Independent: hand drying method
Dependent: variables concerning efficiency
Controlled: N/A We called the El Paso Electric Company to inquire the cost of electricity in our city, as well as the relative waste of the power plant gives off to try and gain perspective of the environmental impact.
We collected data on the average usage of a set number of bathrooms in the school to determine how often the dryers are put to task and paper towels are being used.
Finally, we compiled the data together and looked at the number at a day-by-day and two week period of time to determine the efficiency and cost of both resources. Sources of Error However, one of the biggest obstacles in gathering and collecting the data was the inaccuracy and sheer inability of obtaining the data - many of our results were qualitative than quantitative, and the facts and figures provided by the school district, along with the companies we tried to contact were insufficient to answer our question effectively. Rather, the system in which paper and hand towels are ordered is by a two week cycle. Whether there is a surplus or shortage of paper towels at the end of the two week cycle is not recorded, and official records are not kept except for paper receipts. Due to the sheer size of the school. the wastage of paper towels and the number of times paper towels are replaced, are extremely hard to calculate and record. “As many times as needed” was the given answer by janitors, and we were unable to collect good enough data ourselves due to the limitation of time. Also, calculating the energy consumption of the six total dryers in the boy’s bathrooms was difficult to do. The school only has one energy meter that measures the entire electricity consumption in a given month, whereas the bills are processed by the Central Office. We could not contact them for specific information. The Fastaire HD-03 Hand Dryers are out of issue, quite old and inefficient in comparison to the newer models available. Not only that, the school is more or less entirely based on paper towels - there are a total of six dryers at school, and the comparison between paper towel usage and the outdated dryers specifically at Coronado is not exactly the most equitable.
Rather, we had to generalize specific results for the traffic to the bathrooms and made scientifically sound assumptions to our best judgment. If the experiment were extended without limitations in time and money, an investigation that successfully recorded the total rolls and packages of paper towels used in 1 day, 2 weeks, and 1 month in A and C building, would be most ideal. Finding a way to measure exactly how much energy was spent with the operation of the hand dryers in those buildings (such as how many times these hand dryers are used), would also help tremendously. There are too many lurking variables to accurately conclude from this investigation. Organic Paper Towels:
Many standard, non-organic paper towels bought contain foreign elements and possibly toxic materials, such as bleach, different dyes, to achieve the desired color and texture. However, if the school starts purchasing organic paper towels, these used ‘waste’ can be safely converted into organic mulch for gardening, compost, and animal bedding. In addition, composting is the best way to recycle and cut down on paper towel waste because the process neutralizes toxins and breaks down fibers. It would be quite useful for the Agricultural section of the school in farming and planting. Question Used in rolls and single-folds, they are used in 19 of the 22 bathrooms on campus.
According to the custodial management, towels are replaced on a daily basis.
Ordered every two weeks, the order sizes and costs vary periodically, and no surplus/shortage information is recorded.
The towels, according to manufacturer Tork Universal, are made with 100% recycled fibers and a minimum of 40% post-consumer fibers ***The bathrooms under observation were chosen because comparison between boy’s and girl’s bathrooms, respectively, allowed for a direct comparison between bathrooms with paper towels (girl’s) and bathrooms with hand dryers (boys). Image of Hand dryer utilized at Coronado High School Image of roll paper towels utilized at Coronado High School Paper Towels Hand Dryers Though the girl's bathroom, in comparison, spends around ~$276 for paper towels, yet this is countered by the total amount of money the school spends on paper towels, which costs far more than running the hand dryers. Thus in terms of cost effectiveness, hand dryers emerge as the optimal choice. However, if we looked at the data in the light of comparing the cost in terms of usage of trees versus using fossil fuels and electricity - a comparison of the pollutant output - then things would be quite different. The pollutant output coming from the usage of the hand drivers are, to some extent invalid because the paper towels are made from 100% recyclable materials. If CHS properly utilizes this (see proposed solution) and practices recycling the paper towels dutifully, using paper towels may be more environmentally friendly. The data for the carbon emissions is difficult to ascertain considering data for natural gas and coal volumes used at local power plants that supply most of the energy on the grid supplying Coronado HS with energy was not readily available for the months in question. Keun-woo Lee
Emily Lounder
Nick Quintana
Grace Xu
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