# Presentation: 471817

## Non-Ionizing Radiation:Standards and Regulations

- Bob Curtis, OSHA Salt Lake Technical Center  October 2002

## Power Density vs. Time to Generate Cataracts

- Threshold @ 40 min
- = 100 mW/sq.cm.
- Safety factor of 10
- = 10 mW/sq.cm.

## Applicable OSHA Standards

- 23 States have their own OSHA Standards
- Standards must be at least as strict as Feds
- Most copy Federal standards & interpretations
- Some require a Safety and Health Program
- 1910.97 - Non-Ionizing Radiation
- 10 mW/sq.cm, 6 min. average, 10MHz-100GHz
- No spatial averaging
- Uses voluntary language of 1966 ANSI
- Mandates look of RF Sign

## Applicable OSHA Standards (cont.)

- 1910.268 - Telecommunication Industry
- Primarily safety requirements, such as electrical
- Mandates 1910.97 compliance for 1-300 GHz
- Describes “Tagout” of antenna 3-300 MHz
- 1926.54, 20 - Construction Industry
- Includes tower erection, repairs and painting
- Limits MW to 10 mW/sq.cm. (no averaging)
- Requires Programs to provide safe work to employees and contractors; includes inspection

## OSHA Exposure Standards are Dated

- Construction Laser standard does not include Laser Classification and controls
- RF Exposure Limit is from 1966 ANSI
- Not frequency dependent
- Does not address induced current limits
- Incomplete on Hazard Communication
- Describes RF Sign but not where to use it
- One Warning sign for all conditions
- Incomplete on RF Safety Program Elements

## Applicable OSHA Standards (cont.)

- 1910.147 - Lockout/Tagout of Power
- Requires lockout or tagout of power during maintenance to prevent excessive exposures
- 1910.132 - Personal Protective Equipment
- Requires hazard assessment to select appropriate PPE
- Interpretation letter addresses RF Clothing
- 1910.145, 1926.200 - Signs and Tags
- Use signs to warn of hazards

## Applicable OSHA Standards (cont.)

- 1904 - Record Keeping
- Log of injuries and illnesses, accidents
- 1910.1020 - Access to Employee Exposure and Medical Records
- 1926.20 – Construction Safety Plan
- Section 5(a)(1) of OSH Act
- Requires a safe and healthful workplace free of recognized serious hazards

## Consensus Standards: ACGIH TLVs

- Ultraviolet Radiation
- Light and Near-Infrared Radiation
- Lasers
- Radiofrequency/Microwave Radiation
- Sub-RF and Static Electric Fields
- Sub-RF Magnetic Fields
- Static Magnetic Fields

## Consensus Standards:ANSI Laser Standards

- Z136.1-2000: Safe Use of Lasers
- Z136.5-2000: Safe Use of in Educational Institutions
- Z136.6-2000: Safe Use of Lasers in an Outdoor Environment
- Z136.3–1996: Safe Use of Lasers in Health Care Facilities
- Z136.2-1997: Safe Use of Optical Fiber Communication Systems Utilizing Laser Diode and LED Sources

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## Continuous vs. Pulsed Lasers

- Thinner pulses give higher peaks for same average Power.

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## Slide 13

## Laser Classes

- Class I:  Safe – no label needed
- Do not disassemble Class I systems
- Class II: Visible lasers.
- Aversion response provides protection.
- Prevent staring into beam
- Class IIIa: Visible lasers.
- Limit eye exposure from focusing lenses
- Class IIIb: No eye exposure
- Class IV:  No eye or skin exposure.
- Hazard from diffuse reflections
- Potential fire hazard

**Notes:**
Class 1 – CD ROM player
Class 2 – Grocery Scanner
Class 3 – Laser pointer

## Slide 15

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## Slide 21

## RF Consensus Standards

- IEEE/ANSI (U.S.)
- C95.1 -  RF/MW Exposure limits
- C95.2 -  Signage and S&H programs
- C95.3 – Measurement
- Separate ELF standard
- ICNIRP  (International)
- Single standard 1 Hz to 300 GHz
- ACGIH TLV’s  (US)
- RF/MW, Sub-Resonant E & H

## Basis of Current RF Standards

- Behavioral disruption threshold
- Limit temperature increase to 1 degrees C
- 1-4 W/kg SAR
- 10-fold safety factor

**Notes:**
Notes: 
4 W/kg based on animal behavioral effects is the basis 
Factor of 10 safety factor for whole body in humans (4/10 = .4 W/kg). 
Localized maximums of 20 times the whole body average (.4 x 20 = 8 W/kg). 
Uncontrolled environments limited to 20% of controlled (8 x .2 = 1.6 W/kg). 

## Specific Absorption RateAbsorbed power in Watts/kg

- SAR vs. Frequency

**Notes:**
Notes: Rfmw standards are based on frequency ranges and resonance 
Subresonant (<3 MHz) - Body and parts do not function as good antennas. Current flow considerations dominant throughout. 
Resonant (3 MHz - 6 GHz) - Body becomes good antenna which maximized absorption. 
Current flow and SAR (dose) both important considerations (current flow greater than or equal to 100 MHz). Absorption falls of in proportion to square of frequency from 3 - 30 MHz. 
Standards most stringent from 30 - 300 MHz. 
In transition to next region (from 300 MHz - 3 GHz) adsorption drops off linearly as frequency increases. 
Superesonant (6 GHz - 300 GHz) - Body no longer acts as good antenna, absorption at ~ 1/10 peak absorption. Quasi-optical focusing from 6 - 15 GHz. Skin absorption dominant > 15 GHz (penetration < 1 cm). 

## Slide 25

## RF Exposure Standards are Typically Based on 6 min. TWA

- Excursions allowed if 6 min time weighted average is within limits
- Up to 30 min intervals used for public exposure standards

**Notes:**
Notes: The time-averaging concept can be illustrated as follows. The sum of the product (or products) of the actual exposure level(s) times the actual times(s) of exposure must not be greater then the allowed (average) exposure limit times the specified averaging time. This means that, at 100 MHz, exposure at 2 mW/cm2 would be permitted for 3 minutes in any 6-minute period as long as during the remaining 3 minutes of the 6-minute period the exposure was at or near "zero" level of exposure. Similarly, during any 6-minute period, exposure at 1.5 mW/cm2 would be allowed for 4 total minutes if exposures during the remaining 2 minutes were zero. Another example, 1.5 mW/cm2 would be allowed for 3 minutes and 0.5 mW/cm2 would be allowed for the remaining 3 minutes of a 6-minute period. Therefore, in the first example:
(2 mW/cm2) X (3 min.) + (0 mW/cm2) X (3 min.) = (1 mW/cm2) X (6 min.)
In the second example:
(1.5 mW/cm2) X (4 min.) + (0 mW/cm2) X (3 min.) = (1 mW/cm2) X (6 min.)
And, in the third example:
(1.5 mW/cm2) X (3 min.) + (0.5 mW/cm2) X (3 min.) = (1 mW/cm2) X (6 min.)

## Use of ANSI vs. OSHA vs. FCC Standards

- Newer, more restrictive standards can be used.
- Meeting SAR limits is often easier than field limits.
- New standards allow for spatial averaging, but you have to adopt the whole package.

## Use of ANSI vs. OSHA vs. FCC Standards (cont.)

- Convenient to adopt FCC (with RF current limits).
- OSHA state programs may dictate, but usually defer to newer standards.

## Same Basis, but Standards Differ

- General population vs. Controlled RF Sites
- Localized exposure limits (spatial averaging)
- Time averaging
- Special exclusions, such as low-power devices, peak exposures.

**Notes:**
Notes: 
OSHA uses lower tier as an "action level", e.g., an RF program should exist. 
ANSI assumes 0.4 W/kg is safe for all 
NRPB says 2-tier is not needed. 
ICNIRP justifies lower tier for thermally sensitive, elderly, children, neonates. 

## Safety & HealthPrograms

- OSHA promotes implementing an effective Safety & Health Program
- Many State OSHA’s Already Require
- Required for Federal Agencies
- Required by International Standards (ISO)
- Good Employers will Implement Regardless of OSHA

## What is Needed?Site-Specific RF Program

- Work site Safety and Health Programs should include an RF Program if significant exposures are possible.
- A priority, because S&H Programs can be very effective in preventing excessive exposures.

## Basic Requirements

- Implement an RF program where exposures exceed FCC “General Population” or Public limits (see following slides).
- The RF Program must ensure employee exposure does not exceed FCC “Occupational” limits.

## Hazcom Program should exist for “Uncommonly High” Fields, such as:>50 mG whole body ELF>Uncontrolled limits of FCC

## Perimeter of FCC Uncontrolled Limits

## Perimeter of Controlled Limits indicating need for protective measures (e.g., time averaging)

## Time averaging is not feasible to prevent exposures > MPE’s

## Posted to mark prohibited access without power-down. 

- PPE is not sufficient.

## New Developments Confound Consensus Building

- ICNIRP Standard being adopted more
- Precautionary Principle being adopted by some countries and local governments.
- Regulations regarding Mobile phones & Cellular Tower Sites

## Comprehensive Standard vs. Exposure Limit

- Combination of practices and exposure limits gives more guidance (e.g. ANSI Laser Stds.)
- Exposure limit can be less restrictive.
- E.g.  Protection for all persons vs. exclusions for target populations.
- For each exclusion, you need a program that checks the criteria.

## Predictions 

- Balloting next year on new limit.
- Consensus will drive the standard to be similar to existing version.
- US will continue to drift apart from other countries which will adopt precautionary principle.
- The use of cell phones will continue to rise dramatically.
- Other needed RF standards will proceed, but slow in development.

## Slow Progress on Needed Standards

- RF Safety Program
- RF Awareness (Signs)
- Medical Surveillance and Response
- Measurement Procedures for induced currents
- Criteria for RF Protective Clothing
- Spark Discharge
- Cellular Phones

## Extent of RF Program is Based on Exposure

- Locations are Categorized (I-V) based on potential exposures.
- Many RF exposure situations require no, or a limited RF Safety Program. (Categories I-II)
- More extensive program elements for higher exposure categories.

## Controls/Administrative (cont.)

| Personal Monitors | NN | No | Opt. | Opt. | No |
| --- | --- | --- | --- | --- | --- |
| Incident Response | NN | Yes | Yes | Yes | Yes |
| Medical Devices & Implants | Personal Respon-sibilty | Personal Respon-sibility | Yes, make aware | Yes | Yes |
| Maintenance of Controls | NN | Yes for Public | NN for work.
 | Yes
 | Yes
 |

-                     I            II         III      IV     V

## Proposed Thresholds

- A - Adverse Effect
- B - Effect Preliminary to a Known Adverse Effect
- C - Effect, but Unknown Human Health Consequence
- X - Known Non-Adverse Effect

**Notes:**
Per NIEHS (1999), “ELF-EMF exposure cannot be recognized as entirely safe because of weak scientific evidence that exposure may pose a leukemia hazard; the associations reported for childhood leukemia and adult chronic lymphocytic leukemia cannot be dismissed easily as random or negative findings.”

## For More Informationwww.osha.gov

- Subject Pages on
- Lasers
- RF/Microwave
- ELF
- Includes PowerPoints and Lecture Outlines

## Miscellaneous Slides:Setting Standards

## RF Standard Development

- ANSI C95.1-1966 (OSHA Adopted)
- ANSI 1982 (Frequency dependent)
- ANSI/IEEE 1992 (Two-Tiered)
- IEEE SCC-28 in process.

## IEEE “Culture”

- Engineers/Biologists - few IH’s
- Many representatives of Industry and DoD
- Few Public Safety Regulators
- Standards Based on Known Adverse Health Effects

## Process for Standard Development

- Literature Review
- Engineering
- Animal and Cellular (In Vitro, In Vivo)
- Epidemiology
- Mechanisms
- Risk Assessment
- Consensus

## Problems

- Review process going slow.
- Risk Assessment proceeding.
- Difficulty in getting consensus on basic concepts for a new standard.

## Major Issues to Resolve

- Selection of adverse effect level.
- Basis for local SAR limit.
- Acute vs Chronic exposures.
- Time Averaging
- Uncertainty Factor
- One limit vs Public & Worker limits
- Action Limit and RF Program

**Notes:**
Other issues:
Medical surveillance and emergency response.

- Exposures between B and C occur within known gaps in research, so “Precautionary Principle” or ALARA may be appropriate.
- Precautionary Principle not justified below C level where most exposures occur.

**Notes:**
Concern for low-level exposures causing DNA changes.

Current standard based on heating causing behavior changes (animals reduced their activities and/or avoided the exposure areas.

## Right to Know

- More lenient on threshold if people given choices.

## Purpose and Scope of the ICNIRP Guidelines

- Develop an internally consistent set of exposure guidelines that cover the nonionizing radiation spectrum from 1 Hz to 300 GHz
- The guidelines are intended to provide adequate protection against known adverse impacts on human health resulting from direct and indirect EMF exposure effects.

## UK Stewart Commission

- Preliminary evidence that (phones) may cause, in some cases, subtle biological effects...  (This) does not necessarily mean that health is affected.
- Advocates the “Precautionary” approach until more information.
- Specifically: Labeling of phones; Reduce children use.
- Most points accepted by UK gov’t.

## 1910.268(p)(2)

**Accessible areas** associated with microwave communication systems where the electromagnetic radiation level **exceeds** the radiation protection guide given in § 1910.97 **shall be posted** as described in that section. The lower half of the warning symbol shall include the following:
- Radiation in this area may exceed hazard limitations and special precautions are required. Obtain specific instruction before entering.

## 1910.268(p)(3)

**Protective measures**. When an employee works in an area where the electromagnetic radiation exceeds the radiation protection guide, the employer shall institute measures that **insure that the employee's exposure is not greater than that permitted by the radiation guide**. Such measures shall include, but not be limited to those of an administrative or engineering nature or those involving personal protective equipment.

## Plot of Frequency vs. SAR of Health Effects

## “Modifications” to OSHAStandards

- OSHA Directives to Inspectors and Official Interpretation Letters
- Acceptance of newer ANSI RF Sign
- ANSI Laser Standard Recommended in lieu of outdated OSHA standard.
- Guidance for using RF PPE
- Education of Employers, Employees, and Compliance Staff

## General Duty Clause Criteria

- At Least One Employee Exposed
- It is a Recognized Serious Hazard
- There Are Feasible Means to Correct
- The Employer Knew (Or should have known with reasonable diligence)
- Rely heavily on Consensus Standards
- Even if it Conflict with Existing Standards

## Establishing Employer Knowledge and Feasible Controls

- Common Industry Practice
- Consensus Standards
- “5(a)(1) Letter” to Employers
- Usually based on Consensus Standards
- e.g., ANSI, TLV’s

## Basis for the Safety Factor

- Thermally stressful environments
- Use of alcohol, some medications etc.
- Thermally sensitive
- Normal factor for Public safety due to unknowns in science, health effects, etc.

## IEEE Gives Guidance about Pulsed RFMW

- Pulsed limit = _IEEE cw limit x IEEE averaging time (in secs)_5 x pulse duration (in secs)
- Peak E field < 100 kV/m
- Cw limits apply to situation in which there are more than five pulses during the averaging time

## IEEE Gives Guidance about Pulsed RFMW (cont.)

- Pulsed mw creates mini shock waves which radar operators have reported as clicking sound: may be responsible for eye and neuropharmacological effects reported for pulsed mw according to Lin

## Changes to C95.4-1992 (Supplements)

- Induced current measurements are not necessary for frequencies < 450 kHz (controlled) and < 200 kHz (uncontrolled), or if field strengths are low (e.g., 16% at 27 MHz).
- Changes to the averaging time for RF currents, including prohibition of RF burns.
- Definition of Spatial Average

**Notes:**
Notes: 
Plotted curve of frequency vs. % of field strength MPE. 
Ex., 16% at 2-27 MHz. 

## Changes to C95.4-1992 (Supplements) (cont.)

- Definition of Averaging Volume for Spatial-Peak SAR
- Establishes minimum measuring distance of 5 cm.
- Defines radiated power.

## Spatial Averaging

- ANSI standard is confusing regarding partial-body vs. non-uniform exposure.
- Exception for testes and eyes (See interpretation).
- OSHA standards, based on old ANSI, does not allow for spatial averaging.

**Notes:**
Notes: 
Intended to restrict averaging when a limited part of the body (partial body) is exposed to a high localized field, such as end of a waveguide. 

## Slide 73

## Miscellaneous Slides:RF Exposure Classes

## Proposal for ANSI RF Program Standard

**Class I areas: No signs needed.**
**Class II areas: Notice Signs are suggested**
**Class III areas: Caution Signs are required**
**Class IV areas: Warning Signs are required**
**Class V areas: Danger Signs are required**

## Category I Areas

- Locations where RF fields are too weak to cause exposures greater than the FCC general population (public) limits.
- No dependence on controls, including time averaging.
- NO RF SAFETY PROGRAM NEEDED!!

## Category II Areas

- Potential exposures are controlled to ensure compliance with FCC Public limits.
- Must maintain controls, such as time averaging and shielding, to remain below public limits.

## Category III Areas

- Locations where RF fields are too weak to cause exposures greater than the FCC Occupational limits.
- No dependence on controls, including time averaging.

## Category IV Areas

- Potential exposures are controlled to ensure compliance with FCC Occupational limits.
- Must maintain controls, such as time averaging and shielding, to remain below Occupational limits.

## Category V Areas

- Exposure conditions which can not be controlled to comply with FCC Occupational limits.
- Includes surfaces which will cause serious RF burns if contacted.

## Summary Tables of Program Elements Needed for Each Exposure Category

## Administrative

| Policy | NN | Yes | Yes | Yes | Yes |
| --- | --- | --- | --- | --- | --- |
| Accountable Person | NN | Yes | Yes | Yes | Yes |
| Documentation | NN | Yes, for incidents | Yes | Yes | Yes |
| Employee Involvement | NN | No | Opt. | Yes | Yes |
| RF Safety Committee | NN | No | Opt. | Opt. | Opt. |
| Procurement of RF Source Equipment | NN | Yes | Yes | Yes | Yes |

**                   **I        II        III    IV     V

## Identification of Potential Hazards

| Inventory of RF Sources | NN | Yes | Yes | Yes | Yes |
| --- | --- | --- | --- | --- | --- |
| Exposure Assessment | NN | Initial, + after change | Initial, + after change | Yes | Yes |

**                  **I        II         III       IV      V

## Controls/Engineering

| Utilize low exposure Equip. & Site Configuration  | NN | Yes | Yes | Yes | Yes |
| --- | --- | --- | --- | --- | --- |
| Access Restriction | NN | Opt. | Opt. | Opt. | Yes |
| Maintenance of Controls | NN | Yes | Yes
 | Yes
 | Yes
 |

-                        I       II      III      IV     V

## Controls/Administrative

| Use of Signs | NN | Yes | Yes | Yes
 | Yes
 |
| --- | --- | --- | --- | --- | --- |
| Access Restriction | NN | Opt. | NN | Opt. | Yes
 |
| Work Practices | NN | No | Opt. | Opt. | Opt. |
| Control of Source Power (LOTO) | NN | No | No | Opt. | Opt. |

-   I        II       III      IV       V

## Controls/Administrative (cont.)

| Personal Monitors | NN | No | Opt. | Opt. | No |
| --- | --- | --- | --- | --- | --- |
| Incident Response | NN | Yes | Yes | Yes | Yes |
| Medical Devices & Implants | Personal Respon-sibilty | Personal Respon-sibility | Yes, make aware | Yes | Yes |
| Maintenance of Controls | NN | Yes for Public | NN for work.
 | Yes
 | Yes
 |

-                     I            II         III      IV     V

## Personal Protective Equipment

| Selection of PPE | NN | No | No | Opt.  | When used |
| --- | --- | --- | --- | --- | --- |
| Maintenance, Use, & Accessibility  | NN | No  | No | When used | When used |

-                      I      II      III       IV       V

## Training

| Explanation for RF Exposure Limits  | NN | NN | Yes | Yes
 | Yes
 |
| --- | --- | --- | --- | --- | --- |
| Use & Maintenance of Controls | NN  | Yes, for RFSO | Yes
 | Yes
 | Yes
 |
| Recognizing Abnormal Conditions | NN | Yes, for RFSO | Yes
 | Yes
 | Yes
 |
| Sources of Additional Information | NN | Yes, for RFSO | Yes
 | Yes
 | Yes
 |

-  I       II       III       IV     V

## Program Review

| Adequacy of Present Program Design | NN | Yes | Yes
 | Yes
 | Yes
 |
| --- | --- | --- | --- | --- | --- |
| Implementation (Program in use?)  | NN | Yes
 | Yes
 | Yes
 | Yes
 |

- I      II     III     IV     V

## Examples of the RF Safety Program Elements

## Core Program Elements

- Administrative
- Identification of Potential Hazards
- Controls
- Engineering
- Administrative
- Personal Protective Equipment
- Training
- Program Review

## Administrative

- Policy
- Management Commitment
- Authority to enforce rules
-  Accountable Persons
- Assignment of Duties
-  Documentation
-  Employee Involvement
-  RF Safety Committee
-  Procurement of RF Source Equipment

## Identification of Potential Hazards 

- Inventory of RF Sources
- Exposure Assessment
-  To establish exposure categories.
- To ensure controls are functioning.

## Hazard Assessment Options

- Direct Measurement
- Indirect “Measurement” by comparing to similar sites.
- Model calculations

## Direct Measurement

## PPE and Direct Measurement

- From Ric Tell

## Assess by

- modeling.

## Assess by 

- Assess by
- comparison.
- For example,
- cellulars
- are well
- characterized.
- (See examples
- at end)

## Controls/Engineering

- Utilize low exposure equipment & site configuration
- Use good equipment
- Control hazard areas
- Limit exposures
- Access Restriction
- Maintenance of Controls

## Controls/Administrative

- Use of Signs
- Access Restriction
- Work Practices
- Control of Power Source (LOTO)
- Personal Monitors
- Incident Response
- Medical Devices and Implants
- Maintenance of Controls

## Slides of Example Controls

- Lockout/Tagout
- Personal alarm
- Prevent access to hazardous locations (Signs & Fences)
- Administrative control program
- Protective clothing

## Lock Out / Tag Out

## Lock Out / Tag Out Offers Protection for Workers on Tower

## Personal Alarm

## Cooperative RF Program for Shared Tower

## Cooperative RF Program for Multiple Broadcasters

## Fence to Limit Access

## RF Protective Suits

## PPE Must Be Tested for Application

## PPE Must Be Inspected & Maintained

**From Ric Tell**

## Example Application of Signs Based on Exposure Category

## Sign at entrance to next exposure Category.

## Notice for Public required by FCC. 

- Sign posted at boundary between Category I & II.

## Optional 

- Notice of Worker-based RF Control Program.
- Posted at access points into Category III.

## Caution workers to use Controls

- Posted at access points into Category IV locations.

## Alert to objects which may cause RF shock if contacted without PPE.

## Alert to objects which will cause RF Burns if contacted without PPE

## Posted to mark prohibited access into Category V without power-down or PPE.

- Note: Wrong symbol.

## Posted to mark prohibited access without power-down. 

- PPE is not sufficient.

## Alert to objects which will cause severe RF Burns if contacted.

- PPE may not be sufficient.

## RF Personal Protective Equipment

- If PPE is utilized, a PPE Program must ensure its effectiveness, including proper:
-   Selection of RF PPE within tested capabilities.
-  Accessibility, Use, & Maintenance.

## Training:  What to Teach

- Location of sources and potentially hazardous areas.
- Health effects and safety standards.
- Extent of exposures compared to standards and common sources.
- Required SOP’s and controls.
- Emergency procedures.
- How to know when things are “abnormal”.
- Optional controls employees may use.

## Program Review

- Adequacy of Program Design
- Program Implementation
- Interview employees
- What are the hazards and controls?
- What steps have been taken to enforce the rules?
- Determine what to change, add, and delete.

## Possible Non-Mandatory Appendices

- Example RF Safety Program for a communications company which routinely services/installs antennas on rooftops.
- Appendices concerning PPE and signage

## Example Applications

## Category I Locations

- Most people, including workers, are in Category I locations.
- Therefore, most locations do not need an RF Safety Program.

## Computer Work Station

## Slide 128

## Exposure Locations

## Cell Tower

## ,

## Slide 132

## Slide 133

## Slide 134

## Safety and Health Program Core Elements

- Management leadership and employee participation
- Hazard identification and assessment
- Hazard prevention and control
- Information and training
- Evaluation of program effectiveness

## Exposure While Installing New Antenna

## UIUC

**UIUC**

## Nominal Hazard Zone

## Slide 139

## Slide 140

## Slide 141