42 engineering, technical consultation in the field of construction, security guard services, monitoring of burglar and security alarms, architectural design, chemist services, physician services, engineering services, chemical, dental, medical and optical laboratories, computer programming for others, data collection and gathering in the field of industrial property, rendering technical advice in the field of installations for ventilating, climate control and waste disposal; preparing expert opinions by engineers and scientists in the fields of electrical engineering, mechanical engineering, civil engineering, construction engineering, iron and steel production, aluminium production, power production, waste handling, waste treatment, purification of the environment, water treatment, gas treatment, air purification, denitricication of gas streams and desulphurization of gas streams