Question 2
(a) State three safety precautions to be observed during trench excavation.
(b) Explain the ratio 1:1:2 in relation to mortar mix.
(c) State three preliminary operations that are carried out on a site.
Observation
A good number of candidates were able to:
- state three safety precautions to be observed during trench excavation.
- state three preliminary operations that are carried out on a site.
However, many of them failed to explain the ratio 1:1:2 in relation to mortar mix.
The expected response to question 2 is as given below:
2(a) Three safety Precaution to be observed during trench excavation:
(i)Provision of lighting at night;
(ii)Provision of timbering to safeguard the trench sides;
(iii)Placing warning signs;
(iv)Avoid placing heavy equipment near the trench sides;
(v)Timbering must be inspected before working in the trench.
(b) 1:1:2 in relation to mortar mix
This is a type of mortar in which lime is included in the mix in addition to cement in the
ratio of 1part of cement to 1part of lime to 2 parts of sand.
(c) three preliminary operations that are carried out on site:
(i) Site exploration/ site investigation;
(ii)Site clearing / leveling;
(iii)Construction of access road.