UNE 60601 and the ventilation requirements in combustion machine rooms

In this article, we will explain the main requirements that must be met by premises intended to house cold-heat generation machinery that operates by burning gases. Such requirements are stipulated in the UNE 60601 standard. We will also particularly emphasize those requirements that describe the regulation of the type of ventilation for such premises.

UNE 60601 Standard: Regulation in Machine Rooms

The UNE 60601 standard establishes the requirements that must be satisfied by enclosures intended to house heat or cold generators through heat-transfer fluids or cogeneration equipment (those that generate heat or cold and electricity, using gas as fuel). In both cases, the nominal thermal consumption must exceed 70 kW, and the generating equipment must use gaseous fuels from the families defined in the UNE 60002 Standard.

The UNE 60002 standard, Classification of gaseous fuels into families, classifies gaseous fuels into three families: manufactured gases, natural gases, and mixtures of hydrocarbons-air, and liquefied petroleum gases.

Standalone cogeneration units are located outside. Their ventilation system is outdoors; therefore, they are not required to meet any ventilation requirements. We will then focus on the ventilation requirements of machine rooms.

UNE 60601: Ventilation Requirements

According to the UNE 60601 standard, a machine room can be located either outside the building, connected to it or not, or inside the building. Its internal location can vary: on floors above street level, on the roof, in basements, or in cellars (one floor below street level). If the machine room is located below the building's ground level, the difference between the floor of the room and the building's ground level must not exceed 4 meters.

Parameters to Consider

The standard establishes a series of ventilation requirements based on certain parameters:

• Location of the machine room within the building. • Whether it is an existing building. • Type of gas used in combustion (depending on whether it is denser or less dense than air). • Depending on whether there is a low mechanical resistance partition.

Based on all these parameters, the standard establishes different ventilation systems: natural ventilation, forced ventilation (input) for normal flow, forced ventilation (extraction) for increased flow, detection system, cutoff system, and extraction.

According to the standard, machine rooms must have an air intake (it can be openings in contact with the outside air or can be an air intake through ducts). This air intake must allow adequate combustion of gas in the burners and perfect ventilation of the enclosure.

Ventilation of the Rooms

When the ventilation system is carried out mechanically, it must be considered that the required ventilation flow must be greater than the result of the following expression: Q = 10 × A + 2 × P, where Q is the airflow expressed in m3/h; A is the floor area of the machine room expressed in m2; and P is the sum of the nominal thermal consumption expressed in kW.

If the air intake to the enclosure occurs naturally through a duct, its section must be one and a half times larger than the calculated section. The horizontal sections must not exceed 10 meters. If the gas used in combustion is denser than air, the duct will run, in any case, upward from the outside to the inside of the enclosure.

The air intake for combustion and ventilation can be lower or upper:

Lower Air Intake:

The intake openings must be located so that their upper end is no more than half a meter from the ground. When the gas used for combustion is denser than air, the lower end of the opening cannot be more than 15 cm from the ground. If there are other air intake openings in the room, the distance between them must also be half a meter.

Upper Air Intake:

The openings are located so that the distance from their lower end to the ceiling does not exceed 30 cm. The extraction of indoor air from the room occurs only through openings or ducts that connect directly with outside air.