Development of experimental kiln-drying schedules for different types of coconut (Cocos nucifera L.) palm wood flooring

Abstract

In India, there is a significant gap existing between supply and demand for wood and wood products. Several factors influence wood consumption. For example, the construction sector is witnessing a shift to eco-friendly furnishings. Indeed, the eco-friendly amenity of wooden flooring in hotels and houses has contributed to an upswing in commercial wood consumption. In the current scenario, effective utilisation of existing lesser-known species such as Cocos nucifera L. (Coconut palm tree) is gaining prominence. The lesser known wood species will help to meet the domestic demand and may help to bridge the gap between supply and demand of timber. Seasoning of wood is a crucial step for producing defect-free timber for the ease of doing timber work and potential use of available timber. The purpose of this research is to develop experimental kiln-drying schedules for Cocos nucifera L. (Coconut palm tree) for various flooring methods (Tongue & Groove flooring (T&G flooring), Parquetry flooring, and Engineered overlay flooring). The substructure, base kiln-drying schedules were developed based on the Terazawa method (1965), and optimised using Rasialy (1993) classification. The critical conditions of equalizing treatment and conditioning treatment were established in relation to the product's desirable moisture content, which is 12% for general wood flooring products in climatic zone IV (Kerala). High-density wood samples with thicknesses of 25 mm and 50 mm (20 cm x 10 cm in length and width) were used to investigate drying defects under drastic conditions, and schedules for both thicknesses were developed. Similarly, schedules were developed using medium-density wood samples of 25 mm and 50 mm. The moisture content of the experimental samples (2 cm x 2 cm in length and width) was determined using the oven-dry method, and the basic density was determined based on the water displacement method. 83 The experimental kiln drying schedule recommended for 50 mm thick high-density coconut palm wood Tongue and Groove flooring and Parquetry flooring was MT4-B1 (schedule code). Initial Dry Bulb Temperature 39°C (Relative humidity 89%), Initial Wet Bulb Depression 2°C, and Final Dry bulb Temperature 57°C were the critical conditions for MT4-B1. The highdensity coconut palm wood (25 mm thick) is also suitable for Tongue & Groove flooring and Parquetry flooring and the schedule was MT6-B1 with Initial Dry Bulb Temperature 45°C (Relative humidity 90%), Initial Wet Bulb Depression 2°C, and Final Dry Bulb Temperature 62°C. The recommended experimental kiln drying schedule for medium-density coconut palm wood of 50 mm thickness was MT6-D2 as follows: Initial Dry bulb Temperature 42°C (Relative humidity 87%), Initial Wet Bulb Depression 2°C, and Final Dry bulb Temperature 57°C. The schedule for 25 mm thickness medium-density coconut palm wood was MT6-E1, which includes an Initial Dry bulb Temperature of 42°C (Relative humidity 87%), Initial Wet Bulb Depression of 2°C and a Final Dry bulb Temperature of 45°C. The medium-density coconut palm wood only can be used for overlay flooring because of its low strength. All the schedules are made, considering the desired moisture content (12%) for general flooring purposes under the prevailing conditions of Kerala (Relative humidity > 67%) as prescribed by the Bureau of Indian Standards (BIS).