Posted by Lori Ayre on November 2, 2014

Since the late 1980’s, libraries have been slowly adopting RFID (radio frequency identification) technology as a supplement to barcodes for library material identification and also as a way to replace legacy EM (electro-magnetic) security technologies (e.g. security strips).   RFID provides a single system for efficiently checking in, checking out, and securing library material and because it is based on radiowave technology, it does not require line-of-sight.  Unlike barcodes, which must be scanned one a time, multiple RFID-tagged items can be set on an RFID pad and checked in or checked out.

RFID helps staff work faster and more ergonomically than one-at-a-time barcode systems.  RFID  is also easier for patrons to use at the self-check-out machines.  Not only can staff and patrons check-out multiple items at a time, patrons are also less likely to be confused by the self-check-out process (e.g. distinguishing between barcodes and ISBN tags).

Although there are several benefits to using RFID, adoption has been slow because of the cost of implementing RFID systems and also because the technology was lacking key standards that made investing in RFID somewhat risky – until fairly recently. 

RFID Standards

In 2012, the National Information Standards Organization (NISO) published guidelines for RFID in Libraries.  The publication of these guidelines gave libraries a clear and consistent path forward with RFID.  Prior to this point, products from different RFID vendors were not interoperable nor could tags from one library be read by another library.  Unlike barcodes which can generally be read by any barcode scanner, the content on RFID tags was unreadable from vendor to vendor and library to library.

All this changed in 2012, when NISO established the recommended standard for US libraries to follow (see  The new standard specifies the physical tag that libraries should use (tags must be compliant with ISO 18000-3, Mode 1 and ISO 15693) and the data model that should be used when writing to the tags (ISO 28560-2). 

Since 2012, most RFID vendors have transitioned to the new standard, and virtually all new RFID installations are based on the 2012 Guidelines. This is important because as libraries move to RFID, they will have more flexibility about RFID-enabled devices they can incorporate into their libraries.  Rather than be limited by one vendor’s product lines, libraries can incorporate RFID-enabled devices from any number of vendors (as long as everyone provides ISO 28560-2 compliant products). 

Another reason the adoption of an RFID standard is important is because it supports innovation from the RFID vendors who can now reach out to new customers to sell products.  The concept of a “library’s RFID vendor” will gradually fade away as RFID tags become ubiquitous and standard (like barcodes are already).

RFID and Materials Handling

Automated materials handling (AMH) is fast becoming the standard way of doing business in libraries.  AMH systems usually involve a self-service check-in system (aka “patron return”) combined with a sorter.  Sometimes AMH systems refer to an interlibrary sorter that is used to sort in-transit items only – with no patron return.

AMH systems do not require RFID but many libraries have transitioned to RFID as part of a larger materials handling upgrade so many libraries think RFID is required.  And while self-check-in systems can be implemented in a barcode environment, there are some benefits that are only possible when RFID is employed.

Like self-check-out systems, self-check-in is easier with RFID.  Patrons returning material can place items into the returns without having to orient them with the barcode any particular way.  RFID tags can be read through the book so items can simply be placed in the return or on the conveyor belt to start the return process.

The biggest benefit to using RFID with AMH systems has to do with handling media, especially single disc media sets like movies on DVD.  Without RFID and AMH, staff have to open every DVD case, inspect the media to ensure the right disc is inside and then check it in.  With RFID and AMH, the technology is used to verify that the right disc is inside the case.  In most libraries, this saves a lot of staff time because it saves thousands of instances of opening and closing cases and scanning items. The opening and closing of cases, in particular, is also very costly in terms of ergonomics.  Eliminating this one task will inevitably result in a noticeable reduction in the number of repetitive stress injuries throughout a library system.

AMH Systems Today

Today’s AMH systems are universally quieter, smaller, and easier to maintain than earlier systems.  And the cost of AMH systems has come down while the quality of the systems has gone up.  The advantage of AMH systems is that the entire workflow associated with the patron return is transitioned from a staff mediated process to a self-service process.  Items are identified and checked in by the system and then sorted into bins, totes or carts. 

When deciding how many sort destinations are needed on the sorter, and what type of receptacle is needed (e.g. bin, tote, or cart), the library must analyze their return patterns, return volumes, and consider their shelving needs.  At the very least, a sorter should have three destinations so that items that are ready for reshelving are distinguished from those that need further staff handling (e.g. items that trigger a hold, have a missing piece, are multipart sets) and the third bin can be used for items that need to go out via the interlibrary delivery system (e.g. they just need to go back to their “home” library).

Library Sorters

Early library sorters were little more than industrial-style conveyors that operated with standard book drops.  Today, there are many options for how the self-service return (or check-in) process can work, so it is important for a library to think through the options and decide what is most important. 

Sizes of sorters can range from three bins to over 150 bins (e.g. King County Library system in Washington and New York Public Library) but most libraries have a combination of 5-11 bin systems inside their branches.  Ideally, the sorter should have enough capacity to handle all the returns that come in during library closures so that returns can be accepted 24-7-365. For example, a library that gets 2000 returns per day and is closed one day per week would need an 11-bin sorter (each bin with a capacity of 200 items) so that one whole day’s worth of returns could be accommodated without requiring staff to come in to empty bins (and without having to dump items onto the floor).

There are two basic approaches to self-service check-in and choosing one approach or another generally limits the options. The two approaches have to do with how items are inducted into the sorter. Some sorters require the patron to induct items one-at-a-time and others allow the patron to place two or three into the chute at once.  This approach is referred to as “drop-and-go.”

One-at-a-Time AMH Systems

With one-at-a-time self-service check-ins, the experience is similar to the self-service- check-out process. The patron usually interacts with the system (sometimes with a touchscreen monitor) and most of these systems offer receipts so the patron can verify that their returns were properly checked in. Because the check-in happens at the point of induction, these systems are also sometimes called “intelligent returns.” 

Each patron return is configured with its own RFID reader so the items are read at the start of the transaction.  The benefit of having the item checked in at the beginning of the transaction is that items that are not recognized library items can be rejected.  Most systems offer the library several options for how to handle these exceptions.

In terms of location, the patron return can be an walk-up unit in the foyer, part of an outside drive-up system, or it can be placed inside the library either as a standalone kiosk or built into an internal wall.  Since the self-check-ins are ideally connected to a sorter, the most common place for them is against an external wall as well as in the foyer so libraries can accept returns 24 hours a day. 

Many of the newer internal one-at-a-time returns have ergonomic features such as the ability to raise or lower the height of the counter and screen, use touchscreen technology, and virtually all of them provide multiple language options.

Although it isn’t widely used in the U.S., many of these “intelligent” self-service units can be used for check-in, renewals, and also for check-out. These multipurpose units are perfect for smaller libraries that don’t have room for both a self-check-out machine and a self-check-in machine.  Like other AMH systems, these multipurpose kiosks can be combined with sorters so that returned items are sorted in the back room.  Or the multipurpose kiosks can operate more like a self-check-out system with the option to place returns onto a shelf (which then becomes a Lucky Day collection for incoming patrons to browse) or into a slot (for returns that trigger a hold for another patron).


Some libraries prefer to retain the traditional “book drop” experience for patrons while implementing a new AMH system.  In order to check-in items and to sort them, the returned items cannot be stacked otherwise an item will get sorted incorrectly. So, sorters that don’t require one-at-a-time induction by the patron must do the work instead. A simplified explanation for how these sorters work is that they use a portion of the conveyor to “encourage” items to slide off one another. Once “singulated,” the items can be checked in and sorted correctly. 

The advantage of the “drop-and-go” approach is that patrons can drop items into the slot as they have traditionally done. The process fast and simple and doesn’t require a screen.  Another potential advantage is that the check-in process happens inside the library instead of at the point of the induction.  This makes the cost of the patron return unit cheaper because it isn’t equipped with a RFID reader or any kind of patron interface.

The disadvantage of the drop-and-go system is that items are brought into the library before they have been verified as “library items.”  This means that whatever is placed in the slot ends up in the library (just like with current book drops). For example, if a patron attempts to return library books from the school library, a drop-and-go system cannot return the item to the patron letting them know they are trying to return something other than a public library book.  Also, while, most of these systems offer to mail receipts to the patron, none of these systems can provide printed receipts at the point of return.

Like one-at-a-time returns (and like any book drop), these returns can be placed outside or inside, or at a drive-up. But it is most useful to locate them in the foyer and an external wall close to the backroom where the sorter is located. 

Interlibrary delivery sorters

Library sorters can be used to sort interlibrary delivery as well.  This is a common situation for a main library whose central sort operation is also at the main library.  In this case, the sorter should be equipped with the number of sort destinations needed for the library’s internal sorting needs plus additional sort destinations equipped with interlibrary delivery totes (one or two per library branch).

There are several advantages to using an AMH system for sorting interlibrary delivery items.  One advantage is that the library staff in the branches no longer have to sort items that go to other branches (or put routing slips on them if they don’t sort in the library).  Instead, any item returned to one branch that needs to go to another branch (whether to “go home” or to fill a hold), can just be placed in the same tote.  The library’s courier would transport these items at least once a day to the sorter at the main library where they are inducted onto the sorter by staff to rough sorted for shelving.

The sorter can be configured to sort each branch’s holds separate from returns and can even be configured to keep track of all the items in each distribution tote.  This way, when the items arrive at the branches, they can be checked in all at once via a batch process.  This is particularly handy for a tote full of returns.  From the point of view of staff receiving their library deliveries, all they have to do is scan a barcode on the distribution tote and the sorter software uploads the information to the library system so that each item inside that tote is updated as received.  Staff can immediately reshelve the incoming returns without further handling. 

Holds can happen the same way but it isn’t quite as simple since the Holds slips are generally printed out the same time as there are received.  However, some libraries have found a way to create a combination transit/holds slip that is generated at the point the requested item is placed in transit to the receiving library.

The Role of the Library System

Getting all these systems in place to provide the most efficient materials handling workflow requires cooperation between all the vendor companies involved (e.g. library system, sorter, RFID).  The library system is often the most difficult component to deal with when developing an optimal workflow since they tend to be very protective about what information is shared and how third party products can interact with the system.

Traditionally, the library system has limited the communications that are possible to SIP transactions.  SIP is a protocol developed by 3M for the purposes of standardizing how self-check-out machines communicate with the library system  We now have SIP2 which is more robust than the original version and it is widely supported.  However, it falls short of many of the communications that are necessary to support RFID applications and needed to optimize workflows. 

There are efforts underway to coordinate the development of more expansive communications between third party products (especially related to RFID) in Europe.  Book Industry Communication (BIC) is coordinating these efforts. They are maintaining the Library Communication Framework (LCF) which is intended to coordinate how data is expressed and communicated with the ILS. Relying on diverse and proprietary APIs (application programming interfaces) from each library system vendor locks libraries into a single system so standardizing these communications would benefit all libraries.

See for more information about BIC and the Library Communication Framework.


Ideally, libraries should be able to buy an RFID product or develop a workflow with an AMH vendor that would work with their current library system vendor as well as their next one.  Unfortunately, this is often not the case.  Many third party products, especially when it comes to RFID and AMH, require a significant amount of customization when a library migrates from one ILS to another.  Without an agreed upon framework such as LCF, libraries are still locked into a solution much like they were in the early 1990’s – long before the RFID Guidelines were established by NISO.