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On many Vertical Access projects, we work on roofs or the sides of buildings where there are radio frequency (RF) antennas. Part of our site-specific safety check always involves assessing the risk posed by RF antennas, and we have discussed Radio Frequency Safety in a previous newsletter article. In most of our projects the small number, low power or location of the antennas relative to where we perform our work means that there is little risk from the existing antennas. However, during a site visit a couple months prior to the scheduled field work for the hands-on investigation of the LeVeque Tower in Columbus, Ohio, we noticed a concentration of large antennas beyond what we typically encounter. Below are some of the RF issues that were thoroughly discussed and reviewed both internally and with the project team prior to the inspection. The information presented in this article, intended for those who may come in close proximity to antennas as part of their work but who do not necessarily have training in RF safety, is provided only as general background. Further information is available from some of the links included in the article. In addition, training including basic RF awareness is recommended for those who may be exposed to radio frequencies as an indirect consequence of their work near RF antennas.
The Federal Communications Commission (FCC) is the government body that is responsible for evaluating the effects of FCC-controlled transmitters on the human environment and for developing regulations for Radio Frequency Safety. The FCC’s Rules and Regulations (Title 47 CFR) incorporate recommendations from organizations such as the American National Standards Institute (ANSI), the Institute of Electrical and Electronics Engineers, Inc. (IEEE), and the National Council on Radiation Protection and Measurements (NCRP). In addition, the FCC’s Office of Engineering and Technology publishes information bulletins, such as OET Bulletin No. 56, “Questions and Answers About the Biological Effects and Potential Hazards of Radiofrequency Electromagnetic Fields.”
The FCC requires licensees to assure that that people are not exposed to RF power densities in excess of the applicable Maximum Permissible Exposure (MPE) limit. The FCC defines two tiers of permissible exposures differentiated by the situation in which the exposure takes place and/or the status of the individuals who are subject to exposure. General Population/uncontrolled exposure limits apply to those situations in which persons may not be aware of the presence of electromagnetic energy, where exposure is not employment-related, or where persons cannot exercise control over their exposure. Occupational / controlled exposure limits apply to situations in which persons are exposed as a consequence of their employment, have been made fully aware of the potential for exposure, and can exercise control over their exposure. For an area in excess of 100% Occupational MPE, access controls such as locked doors, signage and administrative policies must be instituted.
Electromagnetic energy includes radio frequency radiation, the portion of the electromagnetic spectrum in the 30 kHZ to 300 GHz range, and is present everywhere. Occupational RF exposure limits relate to the hazard of bodily heating. The eyes and testes are the most susceptible to heating due to low blood flow. A secondary hazard of RF energy is the energization of conductive structures by strong electromagnetic fields. Without any loose wires or stray currents, it is possible to get shocked by an energized structure. RF energy may be dangerous if there is direct contact of an energized material, if the power density is high (such as from multiple sources) or if the exposure time is long. Symptoms of RF exposure are similar to altitude sickness and can include listless or confused behavior, sore joints, dizziness, headaches, bad taste in mouth, blurred vision or nausea.
If working on a building where RF safety is a concern, it is prudent to request a compliance report. The FCC mandates that RF emission levels for any site with an FCC-controlled transmitter be calculated and kept on file. This file must be updated if there are changes to the RF environment. An RF compliance report or emissions study provides additional information. It is a comprehensive evaluation of the emitted electromagnetic energy and RF transmissions, with the findings compared to FCC guidelines for human exposure.
If and RF emissions study or compliance report identifies potential RF hazards, several steps can be taken to mitigate RF exposure when working near antennas. The most straightforward action is to turn off the antennas. Depending on the purpose of the antennas, this cannot always be achieved. Understanding what types of antennas are present in a work area and the specific exposure associated with each antenna, it may be possible to create a temporary controlled access area to avoid entering an RF field that exceeds the MPE. Another mitigation measure is for personnel working near transmitting antennas to wear RF suits. These head-to-toe suits, composed of flameproof Nomex and stainless steel, attenuate the RF signals to reduce their effect and may be appropriate where there are strong RF fields.
Another measure to consider is the use of personal RF monitors. Although personal monitors do not directly mitigate the RF exposure, they do indicate what the exposure at a particular location is. When performing the exterior condition survey of the LeVeque Tower, each technician used a Nardarlert XT A8862 personal RF monitor, capable of detecting frequencies from 100 kHz to 100 GHz . These monitors give an audible and vibratory signal when the field levels above a preset limit are detected. If levels above a certain limit are detected, the user then knows that she should move to another area immediately or limit the amount of time in that area, depending on the reading.
It is important to know that the transmitting signals from two-way radios may exceed 100% MPE as detected by personal RF monitors. We quickly discovered this at the LeVeque Tower when using our Motorola radios, which we always use for on-site communication between technicians. In the case of our radios, this does not become a health concern unless the radio is used in transmission (talk) mode, as posed to the default receiving (listening) mode, more than 50% of the time it is on. As a corollary, the antennas on the building may also interfere with two-way radio signals, creating static or complete disruption of the radio signal.
In the case of the LeVeque Tower, Turner Construction and the property manager shared our concern over RF issues and were extremely cooperative. Prior to the scheduled fieldwork they commissioned an updated RF Compliance Report that focused on the areas where we anticipated working. Most importantly, they turned off the most powerful antennas during our working hours to greatly reduce the RF exposure. During the five days of fieldwork, with each technician wearing a personal RF monitor, we did not encounter RF fields above 100% MPE from the existing antennas. The comfort gained by learning about general and site-specific RF issues before the inspection and the assurance provided from the personal RF monitors used during the inspection were key components to the successful completion of the project.
 Waterford Consultants, LLC, “On-Site RF Emissions Compliance Report,” pepared for LeVeque Tower, dated March 28, 2012.
Mike Gilbert and Keith Luscinski traveled to Golden, Colorado this month to attend the 2012 conference for the Society of Professional Rope Access Technicians (SPRAT). SPRAT is an organization comprised of individuals, companies, and agencies that have a stake in the safe development of rope access standards and practices. Although SPRAT is based in the United States, its scope is international. Currently, SPRAT members hail from the USA, Canada, Mexico, South America, and Europe. The membership includes individual practitioners, companies that provide rope access services, training or equipment, and government agencies.
SPRAT supports rope access practitioners with certification programs, regulatory support, networking, and opportunities to participate in developing industry-consensus standards. The key elements of the conference took place on Thursday and Friday, January 12 and 13.
On Thursday afternoon, a meeting was held by the Standards Committee, which comprises all SPRAT members. The Standards Committee oversees the key subcommittees that maintain and promulgate the current SPRAT standards and formulate new standards. SPRAT has recently been seeing growth in new countries and industries, which was certainly evidenced by the committee’s attendance. Members were present from the USA, Canada, Mexico, Venezuela, Denmark, Sweden, Belgium, and Turkey, as well as from the window cleaning, chimney repair and telecommunication sectors. Vertical Access, however, was one of only a few firms representing the East Coast.
An interesting new development by the Standards Committee is the introduction of a rope access company audit program. This effort is the purview of the Company Audit Subcommittee. Keith attended the subcommittee meeting Thursday afternoon.
Intended to be a voluntary process, the audit would add distinction to businesses that are fully SPRAT compliant. Currently, SPRAT certifies individual technicians but has no process for evaluations at the employer level. This year will likely see a handful of trial runs of the audit program, with a full implementation of the program within the next few years. Vertical Access is interested in this program, and will likely participate in the “beta testing”.
Friday was primarily given over to presentations by the SPRAT membership and interested outside parties and without a doubt, the hottest topic at the conference was Petzl’s presentation of its recent statement regarding the Shunt backup device. Used by the majority of industrial rope access technicians in the United States, the Shunt has been an inexpensive, lightweight and user-friendly fall-protection/backup device for over fifteen years.
Petzl’s recent statement addresses the hazard of an uncontrolled descent should the user either fail to let go of the Shunt or grab the Shunt in the event of a fall or working line failure. While this hazard has been acknowledged by Petzl and rope access practitioners for years, recent testing suggested the previous policy of allowing the Shunt to be used by trained technicians does not adequately mitigate the hazard.
The conclusion is that in spite of our best intentions, we cannot train panic. As part of the statement, Petzl advises against the use of the device for industrial rope access applications. Many industrial rope access companies are now searching for other backup devices that are “panic proof,” meaning that they will arrest a fall even if grabbed by the user.
While every occupation has its hazards, historical data shows an exceedingly low rate of major injuries to industrial rope access technicians. See statistics gathered by the Industrial Rope Access Trade Association.
SPRAT is reviewing its evaluation criteria in light of the previously ubiquitous use of the Shunt device. Vertical Access will begin using an alternative device, while we all await the development of the ideal backup device. Attention all inventors…..
Eighty fall protection professionals representing the fall protection industry throughout the US and Canada gathered in Boulder, Colorado over three days in November to continue moving forward the Z359 fall protection code from the American National Standards Institute (ANSI). Kelly Streeter travels out to this meeting twice a year to take part in this consensus standard writing process. Vertical Access originally became involved in order to be an active subcommittee member of the Z359.8 group: Safety Requirements for Suspended Rope Systems. Chaired by Loui McCurley, representing the Society of Rope Access Technicians (SPRAT), the document is nearly ready to go to the full committee for ballot.
For the past year, Kelly has been the chairperson along with co-chair Steve Hudson, from PMI, of the Z359.9 subcommittee which is tasked with creating the standard for Personal Equipment for Protection Against Falls – Descending Devices. This standard reaches far beyond the world of industrial rope access as we know it at Vertical Access and includes six different types of descenders including devices that are intended solely for rescue purposes. The benefit of these meetings is not only to work on the Fall Protection Code, but also to connect with fall protection professionals outside of the Industrial Rope Access industry.
Kelly Streeter traveled to Boulder, CO during the week of March 21st to participate in the semiannual meeting of the American National Standards Institute (ANSI) Z359 Committee on Fall Protection. Vertical Access has been an active member of the Z359.8 subcommittee, which addresses Rope Access work practices, for more than 5 years. During the last meeting in November of 2010, Kelly was elected as the chairperson of the Z359.9 subcommittee on descending devices.
The Z359.9 subcommittee is lucky enough to have an excellent seed document from the Canadian Safety Association (CSA), which adopted the ISO 22159 Descending Devices document, with a few significant changes. The mandate of the subcommittee is to review the ISO document and to edit, where necessary, to reflect the ideal environment of equipment manufactures, testing and work at height in the United States.
The ISO document identifies eight different types of descenders by characteristics such as the presence or absence of an integral line or a panic brake. Whereas the CSA opted to exclude certain types of descenders, the ANSI subcommittee is hoping to include all of the types of descenders that are currently being used in general industry today. This community is wide and varied and includes consultants investigating and documenting buildings and structures, window washers, arborists and workers in both traditional and emerging power generation industries as well as in many general industry rescue applications. Our goal is to ensure that the testing requirements for individual devices and the training requirements for each type of device are specified so that workers can continue to descend safely in the workplace.
During our meeting in March we identified next steps.
- It was decided that a sub-sub committee would be created to concentrate on reviewing the 56 pages of testing specifications currently in the document.
- Editorial work will be completed so that units reflect the ANSI specified units of measure.
- Other subcommittees will be consulted to ensure that any conflicts between the Z359.9 subcommittee and other subcommittees (specifically Z359.2 on training and Z359.4 on rescue) are identified and resolved.
Our next conference call to discuss progress on these tasks is on May 18th at 1pm EST. If anyone is interested in joining in, please contact Kelly Streeter.
In June 2010, a major wind event passed through New York City and dislodged a large pane of glass from a balcony near the top of the Galleria building in midtown Manhattan, resulting in extensive damage to the glass-enclosed balconies on the south facade of the building. The Galleria, a mixed use building, has an eight-story base with commercial offices and a public atrium, and a 47-story residential tower with “winter garden” balconies above the 19th floor. At the time of its construction in 1975, the building was the tallest concrete-framed structure in New York.
Following the glazing collapse, Vertical Access was retained by Israel Berger & Associates to identify public safety concerns at the winter garden balconies and document the condition of the balconies where the glass had become dislodged as well as the other balconies. The project posed an interesting rigging challenge for Vertical Access, as access to the balconies on the south facade of the Galleria from the rooftop terrace required descending down a curved plexiglass enclosure. To avoid putting weight directly onto the plexiglass panels, founding partner Kent Diebolt and level 3 supervisor Keith Luscinski developed a “ladder” system consisting of aluminum tube spreaders, spanning across the mullions of the enclosure. This allowed VA technicians performing the investigation to safely lower themselves onto the south facade and complete the investigation of the winter garden balconies.
Read about Project 1: Union Theological Seminary Brown Tower
Read about Project 2: University of Buffalo Alumni Arena
Read about Project 3: United States Capitol Dome
Read about Project 4: Boston College Burns Library Tower
Read about Project 5: Mayo Clinic Gonda Building
Read about Project 6: Convent of the Sacred Heart School
The Occupational Safety and Health Administration (OSHA) held a week long public hearing on OSHA’s Proposed Rule on Walking-Working Surfaces and Personal Protective Equipment (Fall Protection Systems), Docket No. OSHA-2007-0072 last week. VA Partners Kent Diebolt and Kelly Streeter both provided testimony to the panel on the last day of the hearing. Kent’s presentation concentrated on the incredible safety record of Industrial Rope Access, as recorded by IRATA, the International Rope Access Trade Association. Kent provided several exhibits that will become a part of the permanent record, including standards and documents published by IRATA, the Society of Professional Rope Access Technicians (SPRAT) and ASTM.
Kelly’s testified on behalf of the American National Standards Institute (ANSI) Z359 committee in her role as the chairperson for the Z359.7 committee on the safety requirements of descending devices.
The goal of the testimony was to educate the panel as to the wide range of industries, equipment and techniques that are affected by the limitations contained in the proposed rule.