Annex IV of NR-7 Control of Exposure to Hyperbaric Conditions

1. CONSTRUCTION WORKERS EXPOSED TO HYPERBARIC CONDITIONS

1.1 Medical examinations, within the standards established in this Annex, are mandatory for work under elevated atmospheric pressure (hyperbaric pressure).

1.2. Medical examinations for workers applying for hyperbaric work must be evaluated by a qualified physician.

1.3 The fitness certificate is valid for 6 (six) months.

1.4 The worker must not undergo more than one compression in a 24 (twenty-four) hour period.

1.5 Professionals performing base release within compressed air caissons for short shifts, up to 30 minutes, may undergo more than one compression in less than 24 hours, up to a maximum of three compressions.

1.6 The worker must not be exposed to pressure higher than 4.4 ATA, except in an emergency, under the direct supervision of a qualified physician.

1.7 The duration of work under compressed air must not exceed 8 (eight) hours at working pressures of 1.0 to 2.0 ATA; 6 (six) hours at working pressures of 2.1 to 3.5 ATA; and 4 (four) hours at working pressures of 3.6 to 4.4 ATA.

1.8 After decompression, workers must stay on the construction site for at least 2 (two) hours for a period of medical observation.

1.9 The appropriate location for the observation period must be designated by the occupational physician responsible for the PCMSO or the qualified physician.

1.10 The qualified physician must be available for contact while there is work under compressed air. In case of a work accident, assistance and an appropriate location for medical care must be provided.

1.11 Every employee working under compressed air must have a medical record in which the data related to the exams performed are recorded.

1.12 If absent from work for more than 15 (fifteen) days or due to illness, the employee must undergo a new medical exam upon return, with the issuance of an ASO.

1.13 If absent from work due to illness for up to 15 (fifteen) days, the employee must undergo a new clinical examination supervised by a qualified physician, without the need for a new ASO.

1.14 If the employee experiences complaints, ear pain, or headache during compression, the compression must be immediately interrupted with a gradual reduction of pressure in the bell until the employee recovers.

1.14.1 If recovery does not occur, decompression must continue to atmospheric pressure, and the employee must be removed and referred to medical services.

1.15 Every employee working under compressed air must be informed about the risks associated with the activity and the precautions to be taken.

1.16 The physical capacity of employees for work in hyperbaric conditions must be evaluated before the start of activities and supervised by a qualified physician.

1.17 Employment of minors under 18 years of age in any hyperbaric environment is prohibited.

1.18 The following complementary exams must be performed for admission and periodic evaluations for work in hyperbaric conditions:

a) Chest X-ray in anteroposterior and lateral views: admission and annual;

b) Electrocardiogram: admission and annual;

c) Complete blood count: admission and annual;

d) Blood type and Rh factor: admission only;

e) Blood glucose level: admission and annual;

f) Bilateral radiography of shoulder, hip, and knee joints: admission and biennial;

g) Audiometry: admission, six months after starting the activity, and then annually;

h) Electroencephalogram: admission only;

i) Spirometry: admission and biennial.

1.18.1 Other complementary exams may be requested at any time at the physician’s discretion.

1.19 Decompression must be carried out according to the tables in this Annex.

1.20 A treatment hyperbaric chamber must be available 24 hours a day, 7 days a week, located such that the worker can be attended to within a maximum of 1 (one) hour after an occurrence.

1.21 The employer must ensure the availability of medical resources at the workplace, including surface medical oxygen, and personnel necessary for first aid in cases of decompression accidents or other events compromising the health of workers. Planning these resources is the responsibility of the occupational physician responsible for the PCMSO or the qualified physician.

1.22 Recompression treatment must be conducted under the supervision of the qualified physician.

1.23 Regarding ventilation, temperature, and air quality, the following conditions must be observed:

a) During the workers’ stay in the work chamber, bell, or airlock, ventilation must be continuous, at a rate of at least 30 cubic feet/min./person;

b) The temperature inside the bell, airlock, and work chamber must not exceed 27°C (twenty-seven degrees Celsius);

c) Air quality must be maintained within the following purity standards: carbon monoxide less than 20 ppm; carbon dioxide less than 2,500 ppm; oil less than 5 mg/m³ (PT > 2 atm); particulate matter less than 3 g/m³ (PT < 2 atm);

d) Oxygen greater than 20% (twenty percent).

1.24 Compression must be carried out at a maximum rate of 0.3 atm in the first minute and must not exceed 0.7 atm in subsequent minutes.

1.25 The organization is not allowed to subject the employee to flights or elevations above 700 meters within 24 (twenty-four) hours following a dry dive.

2. INTERNAL GUIDES FOR MULTIPLACE HYPERBARIC CHAMBERS

2.1 This professional category must be evaluated with the same clinical criteria and complementary exams as item “1. CONSTRUCTION WORKER EXPOSED TO HYPERBARIC CONDITIONS” of this Annex.

2.2 This professional category can be subjected to up to 2 (two) exposures in 24 (twenty-four) hours, under the supervision of a qualified physician.

2.3 The organization is not allowed to subject the employee to flights or elevations above 700 meters within 24 (twenty-four) hours following a dry dive.

3. PROFESSIONAL DIVERS

3.1 For professional diving, activities must be supervised and guided by a qualified physician knowledgeable in diving physiology, choice of gas mixtures, diagnosis, and treatment of diving-related illnesses and accidents.

3.2 All dives must be recorded, including the identification of participating divers and technical data on pressures, times, and composition of the breathed gas.

3.3 For dives using gas mixtures other than air, specific measures must be followed to avoid mistakes, cylinder swaps, and errors in executing decompression stops.

3.4 Occupational medical exams for employees in professional diving must be conducted:

a) Upon admission;

b) Every 6 (six) months for all active diving personnel;

c) After an accident during diving activities or a serious illness;

d) In special situations, other exams may be requested at the physician’s discretion.

3.5 The following complementary exams must be performed for admission and periodic evaluations for professional diving:

a) Chest X-ray in anteroposterior and lateral views: admission and annual;

b) Electrocardiogram or exercise stress test at the physician’s discretion: annual;

c) Echocardiogram: admission only;

d) Exercise stress test: admission;

e) Complete blood count: admission and annual;

f) Blood type and Rh factor: admission only;

g) Blood glucose level: admission and annual;

h) Bilateral radiography of shoulder, hip, and knee joints: admission and biennial, which may be replaced by Magnetic Resonance Imaging or Computed Tomography at the physician’s discretion;

i) Audiometry: admission, six months after starting the activity, and then annually;

j) Electroencephalogram: admission;

k) Spirometry: admission and biennial;

l) Visual acuity: admission and annual.

3.6 Other complementary exams and opinions from other health professionals may be requested at any time at the physician’s discretion.

3.7 Diving activity is prohibited for pregnant and breastfeeding women.

3.8 Compression and decompression must be defined by the qualified physician responsible for the dive.

3.9 All vessels for professional diving work must have a treatment hyperbaric chamber on board for treating diving illnesses or accidents.

3.10 Treatment of diving illnesses or accidents must be supervised by a qualified physician.

3.11 For dives conducted from land bases, a treatment hyperbaric chamber must be available 24 hours a day, 7 days a week, so the diver can be attended to within a maximum of 1 hour after the occurrence.

3.12 The employer must ensure the availability of medical resources at the workplace, including surface medical oxygen, and personnel necessary for first aid in cases of decompression accidents or other events compromising the health of workers. Planning these resources is the responsibility of the qualified physician.

3.13 Diving safety must follow NORMAM-15/DPC in its latest revision.

3.14 The organization is not allowed to subject the employee to flights or elevations above 700 meters within 24 hours following a shallow dive or 48 hours following a saturation dive.

3.15 Recompression treatment must be conducted under the supervision of the qualified physician.

DECOMPRESSION TABLES FOR WORK IN THE CONSTRUCTION INDUSTRY

TABLE 1 – WORKING PRESSURE OF 1 TO 1.9 ATA