Proficiency testing on insulation material thermal conductivity test

OTM participated in a proficiency testing (PT) program recently, with satisfactory results. A PT program is for test quality evaluation of laboratories. Typically, samples with known results are distributed by the PT organizer to a group of participating laboratories. The results tested by the laboratories are compared by the PT organizer to evaluate the test quality of each laboratory.

Below is a summary of the PT program on thermal conductivity testing and the performance of OTM in this program:

  • Number of participating laboratories: 84
  • Test type: insulation material thermal conductivity test
  • Sample: polystyrene board, at 25 °C mean temperature
  • Average results from all laboratories: 0.0344 W/(mK)
  • Result tested by OTM: 0.0344 W/(mK), with Z-score = 0

OTM is SAC-SINGLAS (ISO 17025) accredited for insulation material thermal conductivity testing. We perform both internal and external quality assurance exercises regularly for consistent and reliable measurement accuracy.

Instruments for on-site solar irradiance and daylight illuminance monitoring

A monitoring system was integrated and configured by OTM for on-site solar irradiance and daylight illuminance monitoring. The following Delta Ohm products were used:

The system is a fully automated system. The results are automatically logged and uploaded to the cloud, without site visits and manual operations.

The instruments (left: two sensors; right: wireless data logger)
Result page on Delta Ohm cloud

Solar absorptance and thermal emittance of transparent/translucent materials

We had a post on the sample requirements of translucent membrane products for SRI testing before: SRI testing: Can membrane products be tested without substrate? Essentially, if a transparent/translucent material is to be laid on top of an opaque substrate, it is required to test the transparent/translucent material together with the substrate.

There are also scenarios that transparent/translucent materials are with standalone installations and without substrates, .e.g. canopies made of fabric materials. In such cases, it is sometimes necessary to determine the solar absorptance and thermal emittance of transparent/translucent materials.

Solar absorptance of transparent/translucent materials

According to ASTM E903, the solar absorptance of a transparent/translucent material can be calculated as:

Solar absorptance = 1 – solar transmittance – solar reflectance

The solar transmittance and solar reflectance can be measured with a UV/VIS/NIR spectrophotometer.

Thermal emittance of transparent/translucent materials

It is out of the scope of ASTM C1371 to measure the thermal emittance of a transparent/translucent material. A manufacturer’s technical note is available to measure the IR transmittance and thermal emittance of transparent/translucent materials, with a portable emissometer.

SRI of transparent/translucent materials

It is out of the scope of ASTM E1980 to determine the solar reflectance index (SRI) of transparent/translucent materials. As suggested by its title, ASTM E1980 is for “horizontal and low-slope opaque surfaces”.

Do you test daylight reflectance at different inclination angles?

According to BCA’s requirements on daylight reflectance, there are different requirements for the following installation locations:

  • Facade
  • Low-sloped roof, with less than 20 degrees of inclination angle from the horizontal plane
  • High-sloped roof, with more than 20 degrees of inclination angle from the horizontal pane

We were asked by many customers if we test the daylight reflectance at different inclination angles, in order to meet BCA’s requirements.

The short answer is: no, we do not test the daylight reflectance at different inclination angles.

Daylight reflectance, as a material property, is independent of its inclination angle. The angle in BCA’s requirement is the installation angle, it does not mean that daylight reflectance needs to be tested at various inclination angles.

More explanations

Daylight reflectance is a material property and it does not change with its inclination angle.

For example, for a surface with 10% of total daylight reflectance, its total daylight reflectance remains 10%, when the surface is tilted.

The test angle in the laboratory is dependent on the test instrument design and it is different from the installation angle in a building project.

Thermal comfort data logger for PMV/PPD/WBGT/turbulence measurement

Shown below are two sets of Delta Ohm HD32.3TC thermal comfort data loggers, with the following features:

  • For PMV/PPD/WBGT/turbulence measurement (ISO 7726, 7730 and 7243)
  • 4 quantities measured: air temperature, humidity, speed and globe temperature
  • Portable
  • With large touch screen
  • With built-in Li-ion battery (chargeable via USB)
  • With voice recording and camera function
  • With wi-fi connection for FTP upload

Visit our thermal comfort instrument page for more products.

Career opportunity with OTM: sales executive

We are looking for a sales executive for better sales flow and customer experience.

About us

OTM Solutions Pte Ltd was founded in 2013, with the following two operations:

  • Optical & thermal testing laboratory: we provide third-party material testing services to the building & construction industry (e.g. architectural glass optical properties, insulation material thermal conductivity). Our lab is SAC-SINGLAS accredited and with customers from more than 20 countries.
  • Instrumentation services: we are also the distributor of a well-established instrument manufacturer. We supply measurement instruments (e.g. weather stations and data loggers) and provide integration and measurement services.

For more details, please visit our website:

Job description

We are looking for a sales executive, with the following duties:

  • Pre-sales enquiries: communicate with customers on service/product specifications. Technical knowledge on our services/products is required. Training will be provided.
  • Official sales documents: generate official documents (e.g. quotation, tax invoice, delivery order) required in a typical sales cycle.
  • Post-sales coordination: communicate with customers on job progress and other customer enquiries (e.g. customer feedback and satisfaction survey).
  • Sales records: maintain sales related records in the Customer Relationship Management (CRM) system and other relevant tools (e.g. customer loyalty program, sales records).
  • Quality document management: help laboratory manager maintain quality documents (i.e. standard operating procedures, SOPs) and attend quality audits. Training will be provided.

Job requirements

  • Education: diploma or degree is preferred
  • Language skills: proficient in English (both oral and written) is essential, most communications with customers will be over phone and emails
  • Computer skills: emailing with MS outlook, document editing with MS Word & Excel, quoting and invoicing with software (training will be provided)
  • Professional working and learning attitude: able to learn and comprehend our service/product specifications, able to comply with company requirements
  • Good inter-personal skills and responsive
  • Willingness in working in a small size company
  • Able to work in Woodlands area
  • We welcome fresh graduates to apply

Employment Benefits

  • Fixed basic salary with sales incentives and performance bonus
  • Short office hours (Monday to Friday, 9am – 4pm)
  • 14 days of annual leave
  • Medical benefits

How to apply

Please email your CV and cover letter to If you are shortlisted, we will contact you within 1 week.

Import user IGDB format file into LBNL Optics

On customers’ requests, we can provide the IGDB format files of the glass samples tested by us. Shown below is a screenshot of an IGDB format file:

The IGDB format file can be imported into LBNL Optics and WINDOW for further calculations.

For more detailed operations of the two software tools, please visit the respective help documents. The steps of importing user IGDB format file into LBNL Optics is described below.

Step 1. Create a new Optics user database

Use “Datebase” -> “Create new user database” to create a new user database file *.mdb.

When asked “Do you want to switch to this new (empty) database?”, click “Yes”.

Step 2. Import the IGDB format file

Use “File” -> “Import Text File(s)…” to import the IGDB format file.

Particulate matter (PM1.0, PM2.5 & PM10) measurement with PMsense and wireless data logger

A system was integrated by OTM for construction site particulate matter (PM1.0, PM2.5 & PM10) measurement, with the following components:

  • Delta Ohm PMsense-M particulate matter transmitter with MODBUS-RTU output
  • Delta Ohm HD35EDW-MB wireless data logger supporting MODBUS-RTU output

Listed below are the key specifications:

  • PM measuring principle: laser scattering
  • Calibration certificate can be provided on additional cost
  • Measuring range: 0 – 1000 μg/m3 for each component
  • IP67 protection for both transmitter and data logger, suitable for outdoor installation
  • Wireless connection between data logger and base unit
Left: PMsense-M, right: HD35EDW-MB
Software screenshot

Online luminance contrast calculator V1.0.0

We are pleased to introduce our online luminance contrast calculator (V1.0.0, first version). Click the screenshot below to access this online calculator.

The calculation principle of this calculator is similar to the online total daylight calculator. The luminous reflectances of the two sRGB colors selected are calculated with color space conversion. The luminance contrast is then calculated from the two luminous reflectance results.