NR-33 Health and Safety in Confined Spaces

(SEPRT Ordinance No. 1690, of June 15, 2022)

33.1 Objective

33.1.1 This Regulatory Standard aims to establish the requirements for the characterization of confined spaces, the criteria for managing occupational risks in confined spaces, and the preventive measures to ensure the health and safety of workers who directly or indirectly interact with these spaces.

33.2 Scope

33.2.1 This Regulatory Standard applies to organizations that have or perform work in confined spaces.

33.2.2 A confined space is considered any area or environment that simultaneously meets the following requirements:

a) Not designed for continuous human occupancy;

b) Has limited means of entry and exit; and

c) Where a hazardous atmosphere exists or may exist. A hazardous atmosphere is considered one where one of the following conditions is present:

a) Oxygen deficiency or enrichment;

b) Presence of contaminants with the potential to harm the worker’s health; or

c) Characterized as an explosive atmosphere. Spaces not intended for human occupancy, with limited means of entry and exit, used for storing materials with the potential to engulf or drown the worker are characterized as confined spaces.

33.3 Responsibilities

33.3.1 It is the organization’s responsibility:

a) To formally appoint the technical responsible for fulfilling the assignments provided in item 33.3.2 of this NR;

b) To ensure the means and resources for the technical responsible to fulfill their duties;

c) To ensure that the management of occupational risks includes preventive measures to guarantee the health and safety of workers interacting directly or indirectly with confined spaces;

d) To provide safety sign and lockout of confined spaces to prevent unauthorized entry;

e) To provide initial and periodic training for entry supervisors, attendants, authorized workers, and the emergency and rescue team;

f) To provide information on risks and preventive measures, provided in the Risk Management Program, of NR-01 (General Provisions and Occupational Risk Management), to workers interacting directly or indirectly with confined spaces;

g) To ensure the necessary equipment for controlling risks provided in the Risk Management Program;

h) To ensure the availability of emergency and rescue services, and simulations, when working in confined spaces; and

i) To supervise activities in confined spaces carried out by contracted organizations, observing the provisions of subitem of NR-01, to ensure compliance with this NR.

33.3.2 The technical responsible must:

a) Identify and create a registry of confined spaces;

b) Adapt the entry permit model to include the specificities of the organization’s confined spaces;

c) Develop safety procedures related to the confined space;

d) Indicate the equipment for working in confined spaces;

e) Develop a rescue plan; and

f) Coordinate the initial and periodic training of entry supervisors, attendants, authorized workers, and the emergency and rescue team.

33.3.3 The entry supervisor must:

a) Issue the entry permit before starting activities;

b) Perform tests and check equipment before use;

c) Implement the procedures contained in the entry permit;

d) Ensure emergency and rescue services are available and the means to activate them are operational;

e) Cancel entry and work procedures when necessary;

f) Close the entry permit after completing the services;

g) Perform the attendant’s function when provided in the entry permit; and

h) Ensure the attendant is operational during the work in the confined space.

33.3.4 The attendant must:

a) Allow only authorized workers to enter confined spaces listed in the entry permit;

b) Continuously control the number of authorized workers entering the confined space and ensure all exit at the end of the activity;

c) Stay outside the confined space, near the entrance, in permanent contact or communication with the authorized workers;

d) Activate the internal or external emergency and rescue team when necessary;

e) Operate the personnel movers;

f) Order the abandonment of the confined space whenever recognizing any alarm signal, danger, symptom, complaint, prohibited condition, accident, unforeseen situation, or when unable to effectively perform their duties and cannot be replaced by another attendant;

g) Not perform other tasks during confined space operations; and

h) Communicate to the entry supervisor any unforeseen or abnormal event in the surveillance operation, including when ordering abandonment. The attendant can monitor activities in more than one confined space if the following requirements are met:

a) Stay near the entrances of the confined spaces or nearby, potentially assisted by electronic surveillance and communication systems;

b) All confined spaces must be within their visual range without using electronic equipment;

c) The number of confined spaces must not impair their surveillance duties;

d) The same activity must be performed in all confined spaces under their responsibility;

e) Only two workers are allowed inside each confined space; and

f) Workers must be visible through the confined space access. When assisted by electronic surveillance and communication systems, in accordance with risk analysis and safety procedures, the requirements of subitems can be waived.

33.3.5 Authorized workers must:

a) Follow the instructions received in training and work procedures provided in the entry permit;

b) Properly use the means and equipment provided by the organization; and

c) Inform the attendant or entry supervisor of risk situations for the health and safety of workers and third parties that they become aware of.

33.3.6 The emergency and rescue team must:

a) Ensure the operability of rescue and first aid measures and execute them in case of an emergency; and

b) Participate in the annual rescue simulation exercise covering possible accident scenarios in confined spaces, as provided in the rescue plan.

33.4 Occupational Risk Management in Confined Spaces

33.4.1 The process of identifying hazards and assessing occupational risks, in addition to what is provided in NR-01, must consider the following subitems. The preliminary hazard analysis stage must consider:

a) The existence or construction of new confined spaces where work may be performed;

b) Changes in the geometry or access means of existing confined spaces; and

c) Use of confined spaces that imply changes in previously identified hazards. When work in confined space cannot be avoided, hazard identification and occupational risk assessment must consider:

a) Hazards in the vicinity of the confined space that may interfere with the safety conditions of work in the confined space;

b) The possibility of forming hazardous atmospheres;

c) The need to control hazardous energies in confined spaces; and

d) Other preventive measures described in this NR.

33.4.2 The organization with confined spaces must develop and maintain a confined space registry, including:

a) Identification of the confined space, which may use a code or tracking number;

b) Volume of the confined space;

c) Number of entry openings and manholes, and their dimensions;

d) Access methods, their dimensions, and geometry;

e) Condition of the confined space (active or inactive);

f) Sketch of the confined space (with provision for blockages and isolations); and

g) Use and/or stored product and indication of possible hazards before entry clearance.

33.4.3 When confined space work is performed by a service provider, both the contracting and contracted organizations must meet the following requirements:

a) The contracting organization must provide the contracted organization with the registry of confined spaces where the contracted organization will work;

b) The contracting organization must provide the contracted organization, under subitem of NR-01, with information about occupational risks under its management that may impact the contracted organization’s activities and, where applicable, the preventive measures to be adopted; and

c) The contracted organization must provide the confined space work risk inventory, under item of NR-01, identifying hazards and assessing risks, according to the specifics of the work to be performed, under item of this NR, in the confined spaces where it will work, and implementing preventive measures according to this NR. The contracting organization’s exemption from compliance with this NR does not exempt the contracted organization from gathering necessary information and implementing the preventive measures provided in this Standard.

33.5 Preventive Measures in Confined Spaces

33.5.1 Measures must be taken to eliminate or control the risks of fire or explosion in hot work, such as welding, heating, grinding, cutting, or others that release open flames, sparks, or heat.

33.5.2 The organization performing work in confined spaces must develop safety procedures that include:

a) Preparation, issuance, cancellation, and closing of the entry permit;

b) Requirements for safe work in confined spaces; and

c) Criteria for operating worker movers, when applicable.

33.5.3 Procedures for confined space work must be reviewed when the risk level changes as per NR-01, unauthorized entry, accident, or unforeseen condition during entry.

33.5.4 The organization must develop and implement procedures with requirements and criteria for selecting and using respirators for routine and emergency use, in accordance with respiratory risks.

33.5.5 Every entry and work in confined space must be preceded by the issuance of the entry permit.

33.5.6 The entry permit adopted by the organization must include at least the following fields:

a) Identification of the confined space to be entered;

b) Purpose of entry;

c) Identified hazards and control measures, including the control of hazardous energies, resulting from the risk assessment of the Risk Management Program, according to the activities performed;

d) Identified hazards and preventive measures established at the time of entry;

e) Quantitative atmosphere evaluation, immediately before entry into the confined space;

f) List of entry supervisors, attendants, and authorized workers to enter the confined space, properly listed by full name and function they will perform;

g) Date and time of issuance and closing of the entry permit; and

h) Signatures of entry supervisors and attendants.

33.5.7 The entry permit must be issued in physical or digital form. The entry permit issued in physical form must have two copies, with the first copy remaining with the entry supervisor and the second given to the attendant. The entry permit issued in digital form must meet the following requirements:

a) Be permanently accessible to the attendant during the activity; and

b) Use a certified signature procedure in accordance with NR-01. Electronic devices used for entry permit issuance must:

a) Have an appropriate protection rating for the location of use; and

b) Comply with subitem, when in classified areas.

33.5.8 Issued entry permits must be traceable.

33.5.9 Issued entry permits must be archived for five years. During the archiving period, issued entry permits must be available to workers upon request.

33.5.10 Workers must be informed of identified hazards and control measures before entry into the confined space.

33.5.11 The entry permit must be closed when:

a) Activities are completed;

b) An unforeseen condition occurs;

c) All workers exit the confined space; or

d) There is a substitution of the attendant by another not listed in the entry permit.

33.5.12 The entry permit validity must be limited to one work shift. The entry permit can be extended if the following requirements are met:

a) Relates to the same activities and risks;

b) Records all team stoppage and resumption intervals;

c) Lists authorized workers, attendants, and entry supervisors;

d) Records activity continuity and team substitution at each entry and exit;

e) Ensures continuous monitoring of the entire confined space atmosphere and maintains atmospheric conditions or performs a new atmosphere evaluation at each entry;

f) Ensures the continuous presence of the attendant near the confined space entrance, observed the provisions of subitem of this NR, including during breaks and intervals; and

g) Reassesses the preventive measures described in the entry permit at each entry. The validity of entry permit, including extensions, cannot exceed 24 hours.

33.5.13 Safety Signs Permanent signs must be maintained at all confined space entrances, following the model in Annex I of this NR. If the permanent sign is not visible after opening the confined space, complementary sign must be provided, following the model in Annex I of this NR. In areas with exposure to aggressive agents or circulation of people, vehicles, or equipment, permanent sign must be indelible, ensuring it is not damaged or removed. The requirement in subitem does not apply to existing confined spaces in public roads, except when the access cover is replaced. In the situation in subitem, the application of colors to permanent sign is not required. Temporary sign must be used during entry and work in confined spaces, indicating whether entry is allowed for authorized workers.

33.5.14 Control of Hazardous Energies The control of hazardous energies in confined spaces must be implemented, considering the following stages:

a) Preparation and communication to all involved workers about equipment or system shutdown;

b) Isolation or neutralization of equipment or systems that may interfere with the activity;

c) Isolation or de-energization of equipment or system energy sources;

d) Lockout;

e) Tagging;

f) Release or control of stored energies;

g) Verification of isolation or de-energization of equipment or system;

h) Authorization to start the activity;

i) Withdrawal of workers, tools, and waste after the activity;

j) Communication after the activity ends about the removal of lockout devices and tags, re-energization, and equipment or system restart;

k) Removal of lockouts and tags after activities; and

l) Re-energization or removal of equipment or system isolation devices;

m) Authorization to resume operation. The lockout procedure must ensure:

a) Each worker performing interventions on equipment or systems has an individual independent lockout device;

b) Lockout devices allow the use of individual tags, affixed to lockout points, filled by the workers performing the lockout, containing the service performed, worker’s name, date, and time of lockout;

c) Tags cannot be involuntarily removed or damaged by weather conditions; and

d) Lockout devices and tags are replaced in case of shift changes or team alterations. The removal or replacement of lockout devices or tags by unauthorized persons is prohibited. Neutralizing energy by only interrupting the equipment or system control circuit through command or emergency systems is prohibited.

33.5.15 Atmospheric Evaluations Initial atmospheric evaluations inside the confined space must be performed with the entry supervisor outside the confined space, immediately before worker entry, to verify if it is safe. The oxygen (O2) percentage recommended for entry into confined spaces is 20.9%, with an acceptable range between 19.5% to 23% volume, provided the cause of O2 reduction or enrichment is known and controlled. Atmosphere monitoring must be continuous during worker presence in the confined space, remotely or in person, as per safety procedures. Equipment used for atmospheric evaluations must:

a) Comply with national technical standards or, in their absence, applicable international technical standards;

b) Provide instantaneous readings;

c) Be intrinsically safe;

d) Be protected against electromagnetic radiofrequency interference, capable of withstanding a 10 V/m (ten volts per meter) field;

e) Have simultaneous audible, visual, and vibratory alarms;

f) Have an appropriate degree of protection against dust and water ingress;

g) Have a manual in Portuguese. The auto-zero or clean air adjustment and equipment response test, when used, must be performed daily before evaluations. When the auto-zero or response test fails, the evaluation equipment must be adjusted or parameterized by a trained worker. Equipment calibration must be performed by a laboratory accredited by the National Institute of Metrology, Quality, and Technology (Inmetro).

33.5.16 Ventilation Safe entry conditions, with ventilation, purging, washing, or inertization of the confined space, must be ensured before starting activities. During activities in confined spaces, the following requirements must be met:

a) The ventilation system must be selected and dimensioned according to the confined spaces’ characteristics, following national technical standards or, complementarily, applicable international standards, to ensure air renewal; and

b) Thermal conditions must comply with the provisions of Annex III of NR-09. Ventilation with pure oxygen is prohibited.

33.5.17 Equipment In classified areas, electrical and electronic equipment must be certified or have a document within the National Metrology, Standardization, and Industrial Quality System (Sinmetro). Access to confined spaces with Immediately Dangerous to Life or Health (IDLH) atmospheres is only permitted with a positive pressure demand self-contained breathing apparatus or an airline respirator with an escape cylinder.

33.5.18 Action Plan Preventive measures for confined spaces must be included in the action plan, under subitem of NR-01.

33.5.19 Worker Health Monitoring Workers designated for activities in confined spaces must be assessed for physical and mental fitness, considering psychosocial risk factors. Fitness for confined space work must be recorded in the Occupational Health Certificate (ASO), under NR-07 (Occupational Health Medical Control Program – PCMSO).

33.5.20 Emergency Preparedness In addition to the emergency preparedness established by NR-01, the organization must develop a Rescue Plan for confined spaces, which may be integrated into the emergency plan. The rescue plan must include:

a) Identification of hazards associated with the rescue operation;

b) Designation of the internal or external emergency and rescue team, dimensioned according to the geometry, access, risks of activities, and rescue operation;

c) Response time for emergency assistance;

d) Selection of appropriate techniques, specific personal and/or collective equipment, and available rescue system to reduce the worker’s inert suspension time and exposure to existing hazards; and

e) Provision for simulations of identified scenarios. The organization must ensure that the emergency and rescue team meets the provisions of subitem

33.6 Training

33.6.1 Workers designated for confined space work must be trained in accordance with NR-01.

33.6.2 Entry supervisors, attendants, authorized workers, and emergency and rescue teams must receive initial, periodic, and occasional training, with content, workload, and periodicity defined in Annex III of this NR.

33.6.3 Training must be evaluated to assess the knowledge acquired by workers.

33.6.4 Instructors must have proven proficiency in the content they will teach.

33.6.5 Training must consider the type of confined space and the activities performed, and this information and the technical responsible’s consent provided in item 33.3.2 of this NR must be included in the worker’s certificate, in addition to NR-01 requirements.

33.7 General Provisions

33.7.1 Entry and work in confined spaces are prohibited, ensuring the provisions of subitems 1.4.3 and of NR-01, in any of the following situations:

a) Entry and work in confined spaces without prior authorization;

b) Failure to conduct atmospheric evaluations before worker entry into the confined space and continuous monitoring during activities;

c) Absence of an attendant during worker entry, stay, and exit from the confined space; and

d) Lack of training for entry supervisors, attendants, authorized workers, and rescue teams.

33.7.2 It is recommended to adopt the provisions of ABNT NBR 16577 and its revisions that do not conflict with the provisions of this NR, referring to:

a) Equipment for initial surveying and continuous monitoring of the atmosphere;

b) Emergency and rescue services; and

c) Risk prevention in confined spaces through design.

Annex I – Mandatory Sign for Confined Spaces

Annex II – Entry Permit

Annex III – Training: Course Load, Periodicity, and Program Content