Figure 1 is a hollow brick. Although it has no core holes it qualifies as hollow, according  to ASTM C 652 Section 10.5. Figure 2 is a solid brick. Although  it has core holes, it qualifies as solid according to ASTM C 216 Section 11.1.
Figure 1 is a hollow brick. Although it has no core holes it qualifies as hollow, according to ASTM C 652 Section 10.5. Figure 2 is a solid brick. Although it has core holes, it qualifies as solid according to ASTM C 216 Section 11.1.

Here is a quick and simple quiz: Figures 1 and 2 are brick.

Question #1. Which brick is solid, according to the standard?

Question #2. Which brick is hollow, according to the standard?

Question #3. Explain the difference between solid brick and hollow brick, as defined by ASTM, in 50 words or less.

Update needed

At present, there are two standards for the brick most commonly used in this country: ASTM C 216 Standard Specification for Facing Brick (Solid Masonry Units Made From Clay or Shale) and C 652 Standard Specification for Hollow Brick (Hollow Masonry Units Made From Clay or Shale). They are nearly identical and differ in only two areas: face shell thickness and percent of coring.

The two standards have served the industry well for years; however, innovations and market conditions have made updating them necessary. It is time to publish a single ASTM Standard for Brick for Structure and Facing.

The new standard should present easy ways to specify the right materials for masonry projects. “Solid Brick,” “Uncored Brick,” “Cored Brick,” and “Hollow” should be redefined for clarity. The designer could then refer to the face shell thickness when specifying materials for the drainage wall. The mason contractor could refer to the percent of coring to assist in estimating mortar consumption.

The present standards tell us that “Solid” brick can have holes and “Hollow” brick can be molded without core holes with limitations on frogging and face shell thickness. This wording is very confusing. The definitions of key words in the new ASTM standard should be similar to those in Webster's Dictionary.

The International Residential Code, Chapter 7, is the law for brick veneer on one- and two-family dwellings, which is about 75% of all brick construction. The remaining 25% of brick veneer is built according to the International Building Code. Both of these codes require the wall to be built as a drainage wall.

A drainage wall assumes the some water from wind-driven rain may saturate the brickwork and enter the cavity. Buildings – residential and non-residential – built to the provisions of the two model codes will have a workable drainage system. They will not fail, even if some water penetrates the brickwork.

Brick with coring greater than 25% and face shells 5/8-in. thick have been successfully used to build drainage walls for decades. Publishing a single ASTM Standard for Brick for Structure and Facing will not change anything in the real-world of construction.