RFID's Role in a Fully Integrated, Automated Project Process

This paper provides construction industry owners and contractors with current information about enhancing their operations using radio frequency identification (RFID) technology. Radio frequency identification involves the use of tags, or transponders, that collect data and manage it in a portable, changeable database; communicate routing instructions and other control requirements to equipment; and withstand harsh environments. This paper describes a pilot test using RFID tags to enhance the material management process on an actual construction project. It also investigates ways to integrate RFID technology throughout the project life cycle, improving productivity, cost, schedule, quality, and safety. Introduction Radio frequency identification technology can play an important role in developing a fully integrated, automated project process (FIAPP). The purpose of FIAPP is to reduce overall project cost, schedule, improve quality, and safety during construction as well as facility operations and maintenance. Radio frequency identification involves the use of tags, or transponders, that collect data and manage it in a portable, changeable database; communicate routing instructions and other control requirements to equipment; and withstand harsh environments. It can be viewed as a sister technology to bar code labels which use light waves instead of radio waves to read a tag. An RFID system comprises tags, or transponders, and a reader that, depending on configuration, includes an antenna and scanner. The tag contains a small integrated circuit chip and an antenna that is encapsulated in a protective shell. The reader contains, at a minimum, an antenna and scanner and is used to communicate with the tag. Tags can be categorized as read only or have both read and write capabilities. Moreover, they are classified as active, which means they include a battery, or passive, which means they are powered by the reader’s energy field. The memory capacity of the tags varies from 64 to 32,768 bytes (one byte equals eight bits of binary code). The technology, in existence for several years, is currently being used in several application areas such as vehicle access, personnel identification, asset tracking, livestock identification, and tolls and fees. Application development is currently underway in areas related to groceries, postage stamps, and baggage identification in airports. The primary benefits of using RFID technology are its ability to store data and retrieve it at a later time. In addition, unlike bar code labels, it is more robust because Copyright ASCE 2004 Construction Research 2003 2 RFID tags are not damaged as easily, can be read in direct sunlight, and survive harsh conditions. Limitations include higher tag costs compared to bar code labels; lack of standardization, which prohibits one manufacturer’s reader from reading another manufacturer’s tag; and potential interference from steel objects and other radio frequency signals. Pilot Test This pilot test involved receiving pipe supports and hangers on a Bechtel Power Plant project in Ackerman, Mississippi. Material receipt of pipe supports and hangers is one area of the construction process where RFID technology could improve operations. The current procedure involves unloading and shaking out pallets of supports and hangers, manually “kicking and counting” items, checking them against a packing list, and manually entering data into Bechtel’s material tracking system that calls it PTS, or Procurement Tracking System. This process is time consuming and prone to mistakes. Using the RFID approach, an RFID tag is placed on the pipe support at the supplier’s fabrication plant. Like the manual approach, pallets are still unloaded and shaken out. Workers use a Telxon reader to suit this application; they were trained in the use of the equipment before each test. Using RFID, only one worker is required to kick and count the pipe supports instead of two using the traditional manual approach. The worker scans the tag, populating the screen with information related to the pipe hanger’s purchase order number, release number, and requisition number. Three questions were answered related to each hanger’s quantity, condition, and storage location. This information was then written back to the tag for later use. Once all tags had been scanned, the last step involved downloading the data to the PTS. The pilot test involved a total of 28 hangers with RFID tags. To compare the manual and RFID approaches, time measurements were taken for both methods. The research team initially timed the manual approach used to receive these hangers. Earlier, Bechtel field procurement workers timed the manual approach, using three other shipments of pipe hangers and supports, and provided the research team with these data. Workers were trained for approximately fifteen minutes on the use of the Telxon reader. Figure 1 shows a worker receiving a pipe support using the RFID approach. Copyright ASCE 2004 Construction Research 2003 3 Figure 1: Worker Receiving Pipe Support using RFID Approach The research team used several methods to record observations of this pilot test. A video camera was used to record the entire process, including shaking out the pallets, manually receiving the pipe supports, and receiving pipe supports using RFID. Also, a digital camera was used to provide still photographs of the process. Finally, conversations with the field workers, warehouse supervisor, and other research team members were audio taped for future reference. Table 1 summarizes the time requirements for performing the receipt process using the manual and RFID approaches. The table shows the three steps of the pipe hanger receiving process for the project. This process begins by unloading the trucks and storing the material in the laydown area regardless of approach (manual versus RFID), making the timing of this step the same for both approaches. It is included in this analysis, however, to show the complete cycle. The next step involves unpacking the pallets and receiving the items. For the manual approach, this step means checking off each item from the packing list. The Telxon reader is used to scan the tag and write information back to the tag using the RFID approach. Step 3 involves recording this information into the PTS. As mentioned earlier, Bechtel had made three time studies using the manual approach (refer to the first three columns in the Table 1). Note that the average time to unload one hanger varied from approximately 0.54 minutes to 1.89 minutes. Since the research team was unable to time the unloading process for this pilot test, a simple average, 1.07 minutes, is used, based on the unload times from the previous shipments. The time to manually receive the pipe hangers and supports (includes shaking out pallets and providing verification with packing list) varied from 2.57 minutes to 6.31 minutes. The wide variability in the time it took to complete the receiving process can be explained by some reported unavoidable problems in each trial. For example, in the first manual test (on January 18, 2000), one of the packing lists had item numbers but no tag numbers. Thus, the receivers had to go back and cross reference the items, which required considerable time. In the second manual test (on February 1, 2000), some hangers had no item numbers, and others were not even on the packing list. The time required to receive the pipe supports and hangers using the RFID approach was Copyright ASCE 2004 Construction Research 2003 4 approximately 2.42 minutes. Much of the time savings using RFID results from using only one person for the verification process. Table 1: Pilot Test Time Measurements Method Manual Manual RFID Date 1-18-00 1-24-00 2-1-00 2-10-00 Observer Bechtel Researchers Number of hangers received 166 95 76 28