LEARNING OBJECTIVES

Upon completing this section, you should be able to:

1. Identify and explain the radiation hazards associated with maintaining and operating radar.

2. Identify the safety precautions associated with maintaining radar equipment.

3. Identify safety devices associated with maintaining radar equipment.

4. Identify other hazards associated with maintaining radar equipment.

INTRODUCTION

Throughout your military career, you will be "bombarded" with safety slogans, rules, and procedures concerning almost every job that you do. There is a reason for this. Your command is trying to keep you alive and well. Your part in this process is to become safety "conscious" to the point that you approach every job from the safety point of view. In this chapter, we will address the specific safety measures and devices associated with operating and maintaining radar equipment.

RADIATION SAFETY

One of the hazards associated with maintaining radar equipment is exposure to RFR (Radio Frequency Radiation). Radar peak power may reach a million watts or more. Therefore, you must remain aware of the RFR hazards that exist near radar transmitting antennas. These hazards are present not only in front of an antenna but also to its sides and sometimes even behind it because of spillover and reflection. Exposure to excessive amounts of radiation can produce bodily injuries ranging from minor to major (Think of how food is cooked in a microwave oven.). The extent of injuries depends on the RFR frequency and the time of exposure. At some frequencies, exposure to excessive levels of radiation will produce a noticeable sensation of pain or discomfort to let you know that you have been injured. At other frequencies, you will have no warning of injury. If you suspect any injury, see your ship's doctor or corpsman. Be sure to acquaint yourself with the actual radiation hazard zones of the radar on your ship.

Whenever you work around radar equipment, observe the following precautions to avoid being exposed to harmful RFR:

Do not inspect feedhorns, open ends of waveguides or any opening emitting RFR energy visually unless you are sure that the equipment is definitely secured for that purpose.

Observe all RFR hazard (RADHAZ) warning signs (fig. 3-8). They point out the existence of RFR hazards in a specific location or area.

Ensure that radiation hazard warning signs are available and used.

Ensure that radar antennas that normally rotate are rotated continuously or that they are trained to a known safe bearing while they are radiating.

HAZARDS OF ELECTROMAGNETIC RADIATION

Studies have shown that humans cannot easily sense electromagnetic radiation (EMR), also referred to as radio frequency radiation (RFR). Furthermore, EMR at frequencies between 10 kilohertz (kHz) and 300 gigahertz (GHz) presents a hazard to humans and to some materials. Since radiation at these frequencies is common in the Navy's electromagnetic environment, its presence must be detected and announced to ensure the safety of personnel involved in various activities within the electromagnetic environment. A discussion of the various methods used to detect electromagnetic energy is beyond the scope of this TRAMAN. However, we must emphasize the importance of remaining alert to the danger of overexposure to electromagnetic radiation.

Radiation hazards can be broken down into three categories:

Hazards of Electromagnetic Radiation to Ordnance (HERO)

Hazards of Electromagnetic Radiation to Fuel (HERF)

Hazards of Electromagnetic Radiation to Personnel (HERP)

We will discuss each of these categories in more detail in the following paragraphs.

Hazards of Electromagnetic Radiation to Ordnance (HERO)

The high intensity radio frequency (RFR) fields produced by modern radio and radar transmitting equipment can cause sensitive electroexplosive devices (EEDs) contained in ordnance systems to actuate prematurely. The Hazards of Electromagnetic Radiation to Ordnance (HERO) problem was first recognized in 1958. The prime factors causing the problem have been increasing ever since. The use of EEDs in ordnance systems has become essential. At the same time, the power output and frequency ranges of radio and radar transmitting equipment have also increased.

RFR energy may enter an ordnance item through a hole or crack in its skin or through firing leads, wires, and so on. In general, ordnance systems that are susceptible to RFR energy are most susceptible during assembly, disassembly, loading, unloading, and handling in RFR electromagnetic fields.

The most likely results of premature actuation are propellant ignition or reduction of reliability by dudding. Where out-of-line Safety and Arming (S + A) devices are used; the actuation of EEDs may be undetectable unless the item is disassembled. If the item does not contain an S + A device, or if RFR energy bypasses the S + A device, the warhead may detonate.

Ordnance items susceptible to RFR can be assigned one of three HERO classifications, based upon the probability that they will be adversely affected by the RFR environment. Those classifications are:

1. HERO Safe. An ordnance item sufficiently shielded or protected to make it immune to adverse effects from RFR when used in its expected shipboard RFR environments.

2. HERO susceptible. Ordnance containing EEDs proven by tests to be adversely affected by RFR energy to the point that safety or reliability may be in jeopardy when the ordnance is used in RFR environments.

3. HERO unsafe. Any electrically initiated ordnance item that becomes unsafe when:

a. Its internal wiring is physically exposed.

b. Tests being conducted on the item require additional electrical connections to be made.

c. Electroexplosive devices (EEDs) having exposed wire leads are present, handled, or loaded.

d. The item is being assembled or disassembled.

e. The item is in a disassembled condition.

f. The item contains one or more EEDs and has not been classified as HERO safe or susceptible by either a test or design analysis.

To ensure the HERO safety and HERO reliability of ordnance systems, the Naval Sea Systems Command sponsors an extensive testing program to determine their susceptibility to RFR energy. HERO requirements and precautions are provided in NAVSEA OP 3565/NAVAIR 16-1-529/NAVELEX 0967-LP-624-6010/Volume II, Electromagnetic Radiation Hazards (U) (Hazards to Ordnance) (U). You will find your ship's specific requirements in its HERO Emission Control (EMCON) bill.

The commanding officer of each ship or shore station is responsible for implementing HERO requirements. He or she must also establish a procedure to control radiation from radio and radar antennas among personnel handling ordnance and personnel controlling radio and radar transmitters. The commanding officer does this through a command instruction based on the ship's mission and special features. This instruction is usually part of the Ship's Organization Manual and is the basis for department and division instructions.