SCIENTIFIC NAME
Koompassia spp. principally K. malaccensis, K. excelsa. Family: Leguminosae.
LOCAL NAMES
Impas (Sabah), tualang (Malaysia), tapang, kayu raja, mengris (Sarawak), manggis (Philippines), oempas (Sumatra), ginoo (Palawan), mengaris (Borneo)
DESCRIPTION & NATURAL OCCURENCE
K. excelsa is a very large tree attaining 60 m in height, with high, wide-spreading buttresses and a clean, columnar bole with little taper. The bark is smooth, corky and grey in colour. K. malaccensis is usually smaller, up to 50 m tall, and more slender in form. Species of kempas occur through Borneo, Malaysia, the Philippines, Indonesia and Papua New Guinea.
WOOD APPEARANCE
Colour
Heartwood pink when freshly cut, darkening to a deep orange-brown to red brown after exposure. Sapwood pale yellow to pink-brown and distinct from heartwood.
Grain
Grain is interlocked, spiral or wavy. Texture coarse and even, except when zones of included phloem (bark) present.
WOOD PROPERTIES
Density
880 kg/m3 at 12% moisture content; approximately 1.1 m3 of seasoned sawn timber per tonne.
Strength Groups
S2 unseasoned; SD2 seasoned.
Stress grades
F11, F14, F17, F22 (unseasoned); F17, F22, F27, F34 (seasoned), when visually stress graded in accordance with AS 2082:2000, Timber - hardwood - visually stress-graded for structural purposes.
Joint Groups
J3 unseasoned; JD2 seasoned.
Shrinkage to 12% MC
Approximately 3% (tangential); 2% (radial).
Unit Shrinkage
Not available
Durability Above-Ground
Class 3 - life expectancy 7 to 15 years.
Durability In-Ground
Class 3 - life expectancy 5 to 15 years.
Lyctine Susceptibility
Untreated sapwood susceptible to lyctid borer attack.
Termite Resistance
Not resistant.
Preservation
Sapwood readily accepts preservative impregnation.
Seasoning
Included phloem (bark) causes the timber to split during drying, but clean material seasons well if care taken.
Hardness
Hard (rated 2 on a 6 class scale) in relation to indentation and ease of working with hand tools.
Machining
Interlocking grain can cause difficulty, as does the fibrous nature of kempas. Difficult to work with hand tools.
Fixing
Pre-boring advisable when nailing close to edges. The timber is slightly acidic and may corrode iron fastenings.
Gluing
Can be satisfactorily bonded using standard procedures.
Finishing
Kempas can be sanded to a good finish but requires filling prior to polishing. Stains and accepts paint satisfactorily.
USES
Decorative
Parquetry flooring, panelling, furniture, shop fitting.
Others
Used for railway sleepers, poles, posts in South-East Asia, but not recommended for these applications for long-term use in Australia. Plywood, flooring, decking (but see the note below). Walking sticks, charcoal, shingles, chemical vats, cargo handling pallets.
Note: Stock containing included phloem (bark) has reduced strength and will split when exposed to the weather, making it unsuitable for some applications, such as exposed decking.
IDENTIFICATION FEATURES
General characteristics
Sapwood
Pale yellow to pink-brown, distinct from the heartwood.
Heartwood
Orange-brown to red brown.
Texture
Coarse and even, grain variable but rarely straight.
Wood structure
Growth rings
Indistinct.
Vessels
Diffuse porous arrangement, few in number, medium sized to moderately large, solitary or in radial groups of 2 to 3. Deposits frequently present.
Parenchyma
Aliform and confluent.
Rays
Fine, barely visible with the naked eye.
Other Features
Burning Splinter Test.
Match size splinter burns to a full white ash.
Ripple marks
Present.