Private Area

Information or quotes?

Call us on [+39] 0385.938020 or

Contact us directly

Alisea News


Legionellosis risk at schools: how to prevent it?

Legionellosis often represents a not considered risk in biological risk evaluation of schools, but epidemics have been discovered in environments like schools, hotels and hospitals


Evidences of legionellosis in a Capannoli plant

Security measures has been immediate for the infected rooms. These measures have been activated by a major's decree to debilitate the dangerous bacterium

Working Method

After a documented inspection Alisea carries our remediation work on the aeraulic system, following NADCA certified procedures.

1) Visual Inspection

This consists in a documented inspection, carried out by a specially trained and qualified technician, in order to evaluate the hygiene-maintenance condition of the air treatment system equipment, the discharge terminals, the supply and return air ducts and the cooling towers. Inspections should be carried out at intervals of no more than one calendar year, unless otherwise indicated from previous inspection results or the risk assessment document. In particular a six-month period is recommended for adiabatic humidification systems or in the event of other risk factors for example for climates with high humidity, worn equipment, the presence of sources of pollution of a temporary nature (building sites, excavations, road maintenance work etc...). The results of the checks carried out during the Visual Inspection are recorded in the special Check List and the same activity is also recorded in the Maintenance Register.

2) Technical Inspection

There are two types of Technical Inspection: the Preliminary type which is carried out in the event the Visual Inspection does not manage to clarify all the doubts concerning the hygiene of the system or the type of corrective action to take and is aimed at obtaining a correct view of all the problems that the system has. The Conclusive type which follows the corrective action for maintenance, cleaning and sanitisation is carried out with the precise aim of documenting the results obtained in a comprehensive manner.
In both cases the method used by Alisea , requires complex analytical activity, including the following stages:

  • Technical-structural analysis of the system, aimed at checking it is still suitable to perform all hygienic functions it is intended to. A check should be made on whether the planning choices which were eventually used are compatible with present-day performance needs.
  • Filmed inspection of the internal surfaces and all the components of the system carried out (using special optical probes, fibre optic bore scopes, robotic equipment fitted with high resolution cameras) according to a significant statistical sample of its structure and extension;
  • Quantitative analysis of the particulate and the contaminants deposited on the internal surfaces of the system, to be performed in all Air Treatment Units and in a significant statistical sample of the aeraulic impulse and recirculation ducts.
  • Quantitative analysis of the microbiological agents found inside the system, according to the method of determination on a surface unit, to be performed in all Air Treatment Units and in a significant statistical sample of the aeraulic impulse and recirculation ducts.
  • Quantitative analysis of the fine dust particles dispersed by the system, limited to the inhalable fraction according to the method of determination for air volumes.
  • Quantitative analysis of biological aerosols found in the air conveyed by the system according to the method of determination for air volumes.

3) Corrective Cleaning and/or Sanitising Action

This phase includes total cleaning and disinfection of all the elements in the system that are in a poor hygienic condition, using the most appropriate method (NADCA certified) for the case and the contamination index available on installation. In this phase the following activities are carried out:

  • Total cleaning and disinfection of the Air Treatment Unit, proceeding first with extracting the dust and the deposits present.
    Secondly degreasing washing takes place, performed with suitable certified detergents, used manually or mechanically, according to the characteristics of the system and of the place where remediation activity takes place. During this stage great attention is paid to the thermal exchange batteries, which should be treated on both sides.
    Subsequently a sanitising wash takes place, using a specific germicidal detergent supplied by a saturated steam generator at a temperature of about 80°C.
    The final stage of total disinfection of air treatment units is performed in two phases: by treating all internal surfaces using saturated steam pressure at a temperature of 152°C and by the subsequent aerosolisation of a disinfectant approved by ministerial registration as a “Medical Surgical Device”.
  • Total cleaning and disinfection of the Aeraulic Ducts and the terminal elements starts with an evaluation relating to the need to create inspection ports to access inside the ducts.
    The system is subsequently divided into segments whose sizes vary (from 20 m. to 60 m.) depending on the needs. These system segments are put in depression, by the application of an aspirator fitted with a HEPA filter.
    The workplaces next to the aspirator are compartmentalised with removable environmental containment barriers, in compliance with NADCA procedures.
    The depression which is created inside the ducts is maximum in the centre and near zero near the sides. Therefore, while the aspirator is being used other elements are also used (electro-brushes, wire-guided robots, compressed air probes etc.) which lift all the deposits and carry them up to the point of maximum aspiration, from where they will be captured and conveyed into the aspirator.
    The subsequent disinfection stage intended to eliminate microbiological agents, is performed by the aerosolisation inside the ducts with a disinfectant approved by ministerial registration as a “Medical Surgical Device”.

4) Health and Safety Certification of the system

In the certification phase reporting and advice activities are of prime importance in order to establish a strict regime of legal protection. For companies like Alisea S.r.l. who is UNI EN ISO 14001:2004 and UNI EN ISO 9001:2008 certified it is of fundamental importance that all the documentation and forms produced in this phase are inserted into the “Air Section” in the Environmental Management Manual.

5) Health-Hygiene and Maintenance Plan

In this phase a Health-Hygiene Maintenance Plan is created and drawn up, aimed at keeping health and safety parameters of the system high. All future health-hygiene and maintenance action and the relative time frames are indicated in the plan.

6) Health, Hygiene and Maintenance Register

In this phase a Health, Hygiene and Maintenance Register is drawn up in which all ordinary and extraordinary work carried out on the system is recorded.